Stephen H McKellar

Mayo Clinic - Rochester, Rochester, Minnesota, United States

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Publications (29)129.99 Total impact

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    ABSTRACT: Warfarin is used to reduce the risk of stroke and thromboembolic complications in patients with mechanical heart valves. Yet, despite frequent blood testing, its poor pharmacokinetic and pharmacodynamic profiles often result in variable therapeutic levels. Rivaroxaban is a direct competitive factor Xa inhibitor that is taken orally. It inhibits the active site of factor Xa without the need for the cofactor antithrombin, and thus, its mechanism of action is differentiated from that of the fractionated heparins and indirect factor Xa inhibitors. No in vivo data exist regarding the effectiveness of rivaroxaban in preventing thromboembolic complications of mechanical heart valves. We tested the hypothesis that rivaroxaban is as effective as enoxaparin for thromboprophylaxis of mechanical valves that use a previously described heterotopic aortic valve porcine model. A modified bileaflet mechanical valved conduit that bypassed the native, ligated descending thoracic aorta was implanted into 30 swine. Postoperatively, the animals were randomly assigned to groups receiving no anticoagulation (n = 10), enoxaparin at 2 mg/kg subcutaneously twice daily (n = 10) or rivaroxaban at 2 mg/kg orally twice daily (n = 10). The amount of valve thrombus was measured on post-implantation day 30 as the primary end point. Quantitative evaluation of radiolabelled platelet deposition on the valve prostheses was done and embolic and haemorrhagic events were measured as secondary end points. Animals with no anticoagulation had a thrombus mean of 759.9 mg compared with 716.8 mg with enoxaparin treatment and 209.6 mg with rivaroxaban treatment (P = 0.05 for enoxaparin vs rivaroxaban). Similarly, the mean number of platelets deposited on the valve prosthesis was lower in the rivaroxaban group (6.13 × 10(9)) than in the enoxaparin group (3.03 × 10(10)) (P = 0.03). In this study, rivaroxaban was more effective than enoxaparin for short-term thromboprophylaxis of mechanical valve prosthetics in the heterotopic aortic position. It reduced valve thrombus and platelet deposition on day 30 following implantation without increased adverse events. Future studies would provide additional support for clinical trials evaluating rivaroxaban as an alternative to warfarin for appropriately selected patients with prosthetic aortic valves.
    European journal of cardio-thoracic surgery: official journal of the European Association for Cardio-thoracic Surgery 12/2013; · 2.40 Impact Factor
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    ABSTRACT: Percutaneous intervention of subtotally occluded pulmonary veins can be difficult owing to the cicatrized nature of the stenotic vein tissue. A 55-year-old man with complete left superior and left inferior pulmonary vein occlusions 4 years after repeated atrial fibrillation radiofrequency ablations for symptomatic paroxysmal atrial fibrillation underwent sequential angioplasty, during which an uncovered stent was placed and expanded 2 mm from the pulmonary vein ostium. Hemodynamics rapidly deteriorated, and intracardiac echocardiogram confirmed pericardial tamponade. Median sternotomy was rapidly performed, and a tear encompassing approximately one-third of the circumference of the fibrotic and scarred left upper pulmonary vein was identified. The patient was supported on cardiopulmonary bypass, the heart was arrested, the left atrium was opened, and a covered 10-mm × 10-cm Viabahn covered stent was inserted. Additional external repair of pulmonary vein/epicardial tissue was performed to completely seal the perforation.
    The Annals of thoracic surgery 06/2013; 95(6):2166-2168. · 3.45 Impact Factor
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    ABSTRACT: BACKGROUND: A competent aortic valve is essential to providing effective left ventricular assist device support. We have adopted a practice of central aortic valve closure by placing a simple coaptation stitch at left ventricular assist device implantation in patients with significant aortic insufficiency. We conducted a follow-up study to evaluate the efficacy and durability of this procedure. METHODS: The study included patients who had undergone continuous flow left ventricular assist device implantation. The patients were divided into 2 groups, those who did not require any aortic procedure because the valve was competent and those who underwent central aortic valve closure for mild or greater aortic regurgitation. The clinical endpoints were mortality, progression or recurrence of aortic insufficiency, and reoperation for aortic valve pathologic features. Aortic insufficiency was measured qualitatively from mild to severe on a scale of 0 to 5. RESULTS: A total of 123 patients received continuous flow left ventricular assist devices from February 2007 to August 2011. Of those, 18 (15%) underwent central aortic valve closure at left ventricular assist device implantation because of significant aortic insufficiency (1.8 ± 1.4) and 105 who did not (competent aortic valve, 0.15 ± 0.43; P < .01). At follow-up (median, 312 days; range, 0-1429 days), the mean aortic insufficiency score remained low for the patients with central aortic valve closure (0.27 ± 0.46) in contrast to those without central aortic valve closure who experienced aortic insufficiency progression (0.78 ± 0.89; P = .02). In addition, the proportion of patients with more than mild aortic insufficiency was significantly less in the central aortic valve closure group (0% vs 18%; P = .05). The patients in the central aortic valve closure group were significantly older and had a greater incidence of renal failure at baseline. The 30-day mortality was greater in the central aortic valve closure group, but the late survival was similar between the 2 groups. No reoperations were required for recurrent aortic insufficiency. CONCLUSIONS: The results of our study have shown that repair of aortic insufficiency with a simple central coaptation stitch is effective and durable in left ventricular assist device-supported patients, with follow-up extending into 2 years. Although aortic insufficiency progressed over time in those with minimal native valve regurgitation initially, no such progression was noted in those with central aortic valve closure. Additional investigation is needed to evaluate whether prophylactic central aortic valve closure should be performed at left ventricular assist device implantation to avoid problematic aortic regurgitation developing over time, in particular in patients undergoing left ventricular assist device implantation for life-long (destination therapy) support.
    The Journal of thoracic and cardiovascular surgery 12/2012; · 3.41 Impact Factor
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    ABSTRACT: Abstract  Introduction: Severe tricuspid regurgitation (TR) is present in nearly half the patients undergoing implant of a left ventricular assist device (LVAD) and its correction confers better long-term outcome. Aim: To compare the early and late results of tricuspid valve repair (TVrpr) or replacement (TVR) with LVAD implant. Patient and Methods: Sixty-four from a cohort of 126 patients had a concomitant tricuspid valve procedure; 48 (75%) underwent a TVrpr whereas 16 (25%) had TVR. All preoperative hemodynamic parameters including the mean TR grade (TVrpr; 3.6 vs. TVR; 3.7) were comparable (p = 0.7). The mean TR grade was 1.6 ± 1.5 for the remaining 62 patients who did not have a concomitant tricuspid valve procedure, with 4/62 (6%) having severe TR (p < 0.0001). Results: Cardiopulmonary bypass time was longer for patients undergoing TVR (p = 0.01). There was a significant reduction in right atrial pressure for the entire cohort (p < 0.01) and the postoperative right atrial pressure was not statistically different between TVrpr (13.6 ± 4.6) and TVR (11.6 ± 4.3; p = 0.6. Postoperative intensive care unit stay was comparable as was the duration of inotropic support (p = 0.5) or need for temporary right ventricular mechanical support. In-hospital mortality (12%) was not different between groups. The mean time for LVAD support was 12.3 ± 9.71 months and the last transthoracic echocardiographic examination was performed at mean intervals of 13.8 ± 10.8 months (TVrpr) and 11.8 ± 7.6 months (TVR; p = 0.47). Reduction in TR grade was similar between groups (p = 0.27). Late mortality (p = 1.00) was comparable in both groups. Using log-rank analysis, there was no significant difference in the estimated survival between TVrpr and TVR (p = 0.88). Conclusion: TVrpr repair at the time of LVAD implant is effective in correcting TR even at the end of one year of follow-up. The choice to repair or replace does not affect the clinical outcome. (J Card Surg 2012;27:760-766).
    Journal of Cardiac Surgery 11/2012; 27(6):760-6. · 1.35 Impact Factor
  • Stephen H McKellar, Stephen D Cassivi
    The Journal of thoracic and cardiovascular surgery 10/2012; 144(4):759-61. · 3.41 Impact Factor
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    ABSTRACT: Left ventricular assist devices (LVADs) are increasingly used to treat patients with end-stage heart failure. These patients may develop acute noncardiac surgical problems around the time of LVAD implantation or, as survival continues to improve, chronic surgical problems as ambulatory patients remote from the LVAD implant. Previous reports of noncardiac surgical problems in LVAD patients included patients with older, first-generation devices and do not address newer, second-generation devices. We describe the frequency and management of noncardiac surgical problems encountered during LVAD support with these newer-generation devices to assist noncardiac surgeons involved in the care of patients with LVADs. We retrospectively reviewed the medical records of consecutive patients receiving LVADs at our institution. We collected data for any consultation by noncardiac surgeons within the scope of general surgery during LVAD support and subsequent treatment. Ninety-nine patients received implantable LVADs between 2003 and 2009 (first-generation, n = 19; second-generation, n = 80). Excluding intestinal hemorrhage, general surgical opinions were rendered for 34 patients with 49 problems, mostly in the acute recovery phase after LVAD implantation. Of those, 27 patients underwent 28 operations. Respiratory failure and intra-abdominal pathologies were the most common problems addressed, and LVAD rarely precluded operation. Patients with second-generation LVADs were more likely to survive hospitalization (P = .04) and develop chronic, rather than emergent, surgical problems. Patients with LVADs frequently require consultation from noncardiac surgeons within the scope of general surgeons and often require operation. Patients with second-generation LVADs are more likely to become outpatients and develop more elective surgical problems. Noncardiac surgeons will be increasingly involved in caring for patients with LVADs and should anticipate the problems unique to this patient population.
    Surgery 05/2012; 152(5):896-902. · 3.37 Impact Factor
  • Stephen H McKellar, Hartzell V Schaff
    The Journal of thoracic and cardiovascular surgery 12/2011; 142(6):1591-2. · 3.41 Impact Factor
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    ABSTRACT: The HeartMate II (Thoratec Corp, Pleasanton, Calif) continuous-flow left ventricular assist device has emerged as the standard of care for patients with advanced heart failure. The objective of this study was to assess the safety and early effectiveness of concomitant tricuspid valve procedures in patients undergoing implantation of a HeartMate II device. From February 2007 to April 2010, 83 patients underwent HeartMate II left ventricular assist device implantation. Of these, 37 patients had concomitant tricuspid valve procedures (32 repairs, 5 replacements) for severe tricuspid regurgitation. The effects of a tricuspid valve procedure on tricuspid regurgitation and right ventricular remodeling were assessed comparing echocardiographic findings at baseline and 30 days after left ventricular assist device implantation. Overall survival was also compared. Patients undergoing a concomitant tricuspid valve procedure had more tricuspid regurgitation (vena contracta, 5.6 ± 2.1 mm vs 2.9 ± 2.0 mm; P < .001), worse right ventricular dysfunction (right ventricular end-diastolic area, 33.6 ± 6.2 mm vs 31.6 ± 8.5 mm; P = .05), higher mean right atrial pressure (17.4 ± 7.1 mm Hg vs 14.9 ± 5.1 mm Hg; P = .03), and a higher Kormos score (2.6 ± 2.1 vs 1.2 ± 1.4; P = .0008) preoperatively. One month after surgery, tricuspid regurgitation was worse in patients who underwent left ventricular assist device implantation alone (+18.6%), whereas it improved significantly in patients undergoing a concomitant tricuspid valve procedure (-50.2%) (P = .005). A corresponding significant reduction in right ventricular end-diastolic area (33.6% ± 6.2% vs 30.1% ± 9.7%; P = .03) and a trend toward better right ventricular function (55.5% ± 79.7% vs 35.7% ± 60.5%; P = .28) were noted in patients undergoing a concomitant tricuspid valve procedure. Survival was comparable between the 2 groups. In patients with severe tricuspid regurgitation undergoing left ventricular assist device implantation, a concomitant tricuspid valve procedure effectively reduces tricuspid regurgitation and promotes reverse remodeling of the right ventricle.
    The Journal of thoracic and cardiovascular surgery 08/2011; 143(6):1370-6. · 3.41 Impact Factor
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    ABSTRACT: Laparoscopic Nissen fundoplication is effective for treating gastroesophageal reflux and is usually well tolerated. Some patients, however, experience postoperative dysphagia refractory to conservative measures. We report our experience and operative technique for laparoscopic conversion of previous laparoscopic Nissen fundoplication to partial fundoplication to relieve dysphagia. We retrospectively reviewed the medical records of 6 patients with refractory dysphagia after laparoscopic Nissen fundoplication who underwent laparoscopic conversion to partial fundoplication using a laparoscopic linear stapler. There were no perioperative deaths and no fundoplication-related complications. In short-term follow-up, all patients reported improvement of dysphagia symptoms.
    The Annals of thoracic surgery 03/2011; 91(3):932-4. · 3.45 Impact Factor
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    ABSTRACT: Warfarin reduces risk of stroke in patients with mechanical heart valves but increases risk of hemorrhage and is difficult to use. Dabigatran etexilate, a new oral direct thrombin inhibitor, is safe and effective in reducing risk of stroke among patients with atrial fibrillation. No data exist in the setting of mechanical heart valves. We tested the hypothesis that dabigatran etexilate is as effective as heparin for thromboprophylaxis of mechanical valves in a porcine heterotopic aortic valve model. Thirty swine underwent implantation of modified bileaflet mechanical valved conduit bypassing the ligated, native descending thoracic aorta. Animals randomly received no anticoagulation (n = 10), enoxaparin 2 mg/kg subcutaneously twice daily (n = 10), or dabigatran etexilate 20 mg/kg orally twice daily. Primary end point was amount of valve thrombus at 30 days. Secondary end points included quantitative measurement of platelet deposition on valve prosthesis, thromboelastography, and hemorrhagic and embolic events. At 30 days, we observed 638 ± 895 mg thrombus in no anticoagulation group, 121 ± 128 mg in enoxaparin group, and 19 ± 31 mg in dabigatran etexilate group (P = .01 enoxaparin vs dabigatran etexilate). Fewer platelets were deposited on valves in dabigatran etexilate group (2.7 × 10(8)) than in enoxaparin group (1.8 × 10(9), P = .03). No major or occult hemorrhagic or embolic events were observed. By thromboelastographic analysis, dabigatran etexilate produced less prolongation of K value (P = .01) and less decreases in angle (P = .01) and maximum amplitude (P = .001) than enoxaparin. Dabigatran etexilate is as effective as enoxaparin for short-term thromboprophylaxis of mechanical valves. It prevents valve thrombus and platelet deposition at 30 days without increased adverse events. These promising results serve as a foundation for prospective clinical trials with dabigatran etexilate as an alternative to warfarin in patients with bileaflet mechanical aortic valves.
    The Journal of thoracic and cardiovascular surgery 03/2011; 141(6):1410-6. · 3.41 Impact Factor
  • Journal of Heart and Lung Transplantation - J HEART LUNG TRANSPLANT. 01/2011; 30(4).
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    ABSTRACT: Pregnancy and congenitally bicuspid aortic valve (BAV) are thought to be risk factors for aortic dissection; however, the population-based risk for patients with the 2 risk factors remains unknown. We investigated the relation between pregnancy and ascending aortic events in women with congenital BAV living in Olmsted County, Minnesota. Our institutional echocardiographic database was searched for women residing in Olmsted County with congenital BAV diagnosed from 1980 to 1999. We reviewed medical records for end points of aortic events (dilatation, dissection, or surgery) and aortic valve replacement (AVR). Obstetric history and further outcome follow-up were collected by postal survey. We identified 88 women with BAV. Median age at diagnosis was 35 years. Obstetric history totaled 216 pregnancies and 186 deliveries. There were no aortic dissections. During follow-up (median 12.3 years), 24 patients underwent AVR (n = 14), ascending aortic surgery (n = 3), or AVR and ascending aortic surgery (n = 7). Pregnancy was not associated with dilatation of the aorta, aorta surgery, or AVR. At echocardiographic diagnosis of BAV, 5 patients (6%) had aortas >40 mm in greatest diameter and 1 patient has >50 mm. Of 60 patients with serial echocardiograms for comparison (median interval 10.7 years), 21 patients (35%) had aortas measuring >40 mm in greatest dimension and 2 patients had >50 mm. In conclusion, aortic dissection in women with BAV and pregnancy is rare in the community. There is a significant rate of progressive enlargement of the aorta, warranting longitudinal follow-up.
    The American journal of cardiology 01/2011; 107(1):96-9. · 3.58 Impact Factor
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    ABSTRACT: Bicuspid aortic valve (BAV) is associated with ascending aortopathy predisposing to aneurysmal dilatation and dissection, even after successful aortic valve replacement (AVR). There is, however, scant evidence on which to make recommendations for prophylactic replacement of the ascending aorta at the time of AVR. The medical records of patients who underwent AVR for BAV without aortic replacement or repair from 1960 to 1995 were reviewed. Follow-up was by review of the medical record and postal questionnaire. Among 1,286 patients, the mean age at operation was 58 ± 14 years. During the follow-up interval (median 12 years, range 0 to 38), there were 13 documented aortic dissections (1%), 11 ascending aortic replacements (0.9%), and 127 documented cases of progressive aortic enlargement (9.9%). Fifteen-year freedom from aortic dissection, enlargement, or replacement was 89% (95% confidence interval [CI] 87% to 91%) and was lower in patients with documented aortic enlargement at the time of AVR (85%, 95% CI 81% to 89%) compared to those whose aortic dimensions were normal (93%, 95% CI 90% to 96%) (p = 0.001). Multivariate predictors of aortic complications included interval (subsequent) AVR (hazard ratio [HR] 3.5, 95% CI 2.3 to 5.4, p <0.001), concomitant coronary artery bypass grafting (HR 2.6, 95% CI 1.7 to 4.0, p <0.001), enlarged aorta (HR 1.8, 95% CI 1.3 to 2.6, p = 0.001), and history of tobacco abuse (HR 1.8, 95% CI 1.2 to 2.6, p = 0.003). Aortic dilatation did not predict mortality. In conclusion, despite a true risk for aortic events after AVR for BAV, the occurrence of aortic dissection was low. Any incremental surgical risk imposed by prophylactic replacement of the ascending aorta must be equally low.
    The American journal of cardiology 12/2010; 106(11):1626-33. · 3.58 Impact Factor
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    ABSTRACT: Lung transplant is an effective treatment for patients with end-stage lung disease but is limited because of the shortage of acceptable donor organs. Organ donation after cardiac death is one possible solution to the organ shortage because it could expand the pool of potential donors beyond brain-dead and living donors. We report the preliminary experience of Mayo Clinic with donation after cardiac death, lung procurement, and transplant.
    Mayo Clinic Proceedings 02/2010; 85(2):150-2. · 5.79 Impact Factor
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    ABSTRACT: The aortic mechanical prosthesis (AMP) generates shear stress and causes erythrocyte fragmentation with ADP release that leads to platelet activation, the cause of thromboembolism. Thromboprophylaxis with the antiplatelet agents clopidogrel and aspirin (Clop-ASA) should reduce thromboembolic events in patients receiving an AMP. Over an eight-year period at the authors' institutions, a total of 135 patients underwent aortic valve replacement (AVR), with or without concomitant thoracic aortic procedures, and received Clop-ASA as thromboprophylaxis. Platelet reactivity was measured using the Verify Now system. Thromboelastography was commenced in August 2006, and patients were followed at six-month intervals, with echocardiography and assessment of platelet reactivity. The total follow up was 4,776 months (equivalent to 398 patient-years (pt-yr)); the average follow up was 35.4 +/- 25 months. During follow up, 18 patients (13.3%) died, eight from coronary artery disease and three from valve-related causes. Five patients (3.7%; 1.2%/pt-yr) had bleeding complications, but none experienced valve thrombosis. Two patients (1.5%; 0.5%/pt-yr) had a transient ischemic attack (TIA); one of these occurred in a patient who discontinued Clop-ASA, and the other in a responder to Clop-ASA. Seven patients (5.2%; 1.7%/pt-yr) had strokes, one of which occurred at 48.5 months after AVR. Of the remaining six patients who had a stroke, one was a non-responder to clopidogrel and five had stopped taking Clop-ASA. The incidence of strokes before using the Accumetrics and TEG devices was 2.5% per pt-yr, but only 1.0% per pt-yr thereafter. Thromboprophylaxis in patients with AMP receiving Clop-ASA seems to be effective. Patients had a low incidence of bleeding, TIA and ischemic stroke, and no valve thrombosis. The use of assays to determine platelet reactivity helped to identify those patients who were resistant to clopidogrel, hyporesponders, and poorly compliant patients. Notably, the incidence of strokes after implementing assays to monitor platelet reactivity was reduced. Deaths were due primarily to myocardial infarction, and none of the deaths was anticoagulant-related. Patients receiving Clop-ASA should undergo routine testing of platelet reactivity, and also continue antiplatelet therapy so as to reduce the risk of ischemic stroke.
    The Journal of heart valve disease 11/2009; 18(6):617-25; discussion 626. · 1.07 Impact Factor
  • Stephen H McKellar, Thoralf M Sundt
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    ABSTRACT: Aortic valve disease is frequently associated with proximal aortic aneurysmal disease. While, there are clear indications for aortic valve replacement, the ideal type of valve prosthesis, mechanical versus biologic remains controversial. This controversy becomes even more complex when the proximal aorta requires replacement as root replacement is more challenging and reoperative surgery following root replacement is even more so. In addition, not all proximal aortic aneurysms behave the same way; Marfan's aneurysms behave more aggressively than non-Marfan's aneurysms. The variance in aneurysm behavior mandates a clear understanding of the biology and consequent natural history of each patient's aortic aneurysm. In this review, we discuss valve replacement options for patients requiring aortic valve replacement and concomitant proximal aortic replacement.
    Future Cardiology 08/2009; 5(4):375-83.
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    ABSTRACT: Most aortic valve replacements are by conventional full median sternotomy. Less invasive approaches have been developed with partial upper sternotomy (ministernotomy). Systematic review and meta-analysis were performed with studies comparing ministernotomy and full sternotomy for aortic valve replacement. Twenty-six studies were selected, with 4586 patients with aortic valve replacement (2054 ministernotomy, 2532 full sternotomy). There was no difference in mortality (odds ratio 0.71, 95% confidence interval 0.49-1.02). Ministernotomy had longer crossclamp and bypass times (weighted mean difference 7.90 minutes, 95% confidence interval 3.50-10.29 minutes, and 11.46 minutes, 95% confidence interval 5.26-17.65 minutes, respectively). Both intensive care unit and hospital stays were shorter with ministernotomy (weighted mean difference -0.46 days, 95% confidence interval -0.72 to -0.20 days, and -0.91 days, 95% confidence interval -1.45 to -0.37 days, respectively). Ministernotomy had shorter ventilation time and less blood loss within 24 hours (weighted mean difference -2.1 hours, 95% confidence interval -2.95 to -1.30 hours, and -79 mL, 95% confidence interval -23 to 136 mL, respectively). Randomized studies tended to demonstrate no difference between ministernotomy and full sternotomy. Rate of conversion from partial to conventional sternotomy was 3.0% (95% confidence interval 1.8%-.4%). Ministernotomy can be performed safely for aortic valve replacement, without increased risk of death or other major complication; however, few objective advantages have been shown. Surgeons must conduct well-designed, prospective studies of relevant, consistent clinical outcomes to determine the role of ministernotomy in cardiac surgery.
    The Journal of thoracic and cardiovascular surgery 04/2009; 137(3):670-679.e5. · 3.41 Impact Factor
  • Stephen H McKellar, L Ray Matthews
    New England Journal of Medicine 02/2009; 360(5):e7. · 54.42 Impact Factor
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    ABSTRACT: : Delivery of a collapsable aortic valve prosthesis via the left ventricular (LV) apex has proven problematic clinically. We describe our experience with a novel technique for a laparoscopic transdiaphragmatic approach to the LV outflow tract (LVOT). : Laparoscopic transabdominal access to the left ventricle was achieved in four live swine and one human cadaver using three abdominal laparoscopic trocars. Pericardioscopy and cardioscopy were performed. A hemostatic purse-string suture was placed laparoscopically at the apex of the left ventricle in one pig, and an instrument passed through the purse-string and into the LVOT. After the procedure, a thoracotomy was performed and the heart explanted for gross examination. : Transdiaphragmatic exposure of the LV apex was accomplished at a mean of 23 minutes. Hemodynamic stability was maintained in all animals and the pleural cavities were not violated. Pericardioscopy allowed visualization of both right and left pulmonary veins along with the left atrial appendage. In situ cardioscopy confirmed that access to the LVOT and the aortic annulus was possible from the LV apex entry site. : Laparoscopic transdiaphragmatic approach to the LVOT is a possible route for minimally invasive beating heart aortic valve implantation. This strategy permits a straight transapical line of access to the aortic valve; avoiding the potential for cardiac torsion via a thoracotomy.
    Innovations Technology and Techniques in Cardiothoracic and Vascular Surgery 01/2009; 4(1):27-31.
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    ABSTRACT: Hemostatic agents are frequently used during abdominal surgery and some are linked to adhesion formation. We sought to evaluate the impact of several commonly used hemostatic agents on adhesion formation in a rat peritoneal model. In our study, Wister outbred rats underwent laparotomy and excision of a portion of their peritoneum to initiate adhesion formation process. One of six different hemostatic agents, namely, activated starch microspheres (Arista AH; Medafor Inc., Minneapolis, MN), glutaraldehyde activated collagen (BioGlue; Cryolife Inc., Kennesaw, GA), thrombin coated collagen microspheres (FloSeal; Baxter Inc., Deerfield, IL), thrombin activated fibrin polymer (Tisseel, Baxter), polyethylene glycol polymer (CoSeal, Baxter), or oxidized cellulose (Surgicel; Ethicon Inc., Somerville, NJ), was placed in the area of peritoneal defect. All animals were sacrificed on post-op day 7 and strength and extent of adhesion formation was determined. Histopathological examination of rat caecum was also performed. Arista and CoSeal showed significantly lower adhesion formation than controls (P < 0.05). Higher adhesion scores were seen in BioGlue (P < 0.05) treated rats. Additionally, histopathologic examination showed that BioGlue caused statistically more inflammation and necrosis than controls (P < 0.05). Total adhesion score increased with residual amount of agent present at 7 d. Use of Arista and CoSeal may help in reducing peritoneal adhesions after intra-abdominal surgeries. Furthermore, there appears to be a relationship between the creation of inflammation and necrosis in tissues and the eventual formation of adhesions. This could aid in improving the design of these agents in the future.
    Journal of Surgical Research 11/2008; 155(1):77-81. · 2.02 Impact Factor

Publication Stats

300 Citations
129.99 Total Impact Points


  • 2006–2013
    • Mayo Clinic - Rochester
      • • Department of Cardiovascular Surgery
      • • Department of Surgery
      Rochester, Minnesota, United States
  • 2012
    • University of Utah
      • Division of Cardiothoracic Surgery
      Salt Lake City, UT, United States
  • 2007–2012
    • Mayo Foundation for Medical Education and Research
      • • Department of Surgery
      • • Division of Vascular Surgery
      • • Mayo School of Graduate Medical Education
      Scottsdale, AZ, United States