Robert W Chang

Dartmouth–Hitchcock Medical Center, Lebanon, NH, USA

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Publications (6)19.9 Total impact

  • Article: A percutaneous arterial closure protocol can decrease complications after endovascular interventions in vascular surgery patients.
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    ABSTRACT: Complications following percutaneous femoral access are a significant source of morbidity and cost in patients undergoing peripheral vascular interventions. Our purpose in this study is to determine if access complications could be reduced by the use of a standardized protocol. We studied prospectively 210 consecutive patients in our vascular surgery practice undergoing peripheral arterial interventions via percutaneous retrograde femoral access. First, we prospectively collected data to determine current outcomes during a 4-month observation phase. Based on these experiences, we designed and implemented a uniform arterial closure protocol, with closure device use guided by sheath size, arterial calcification, and previous groin scarring. Our main outcome measures were major complications (need for operation) or minor complications (access site bleeding or hematoma). Outcomes were compared between the two phases using chi-squared analysis and analysis of variance (ANOVA). In the observation phase, 119 patients underwent 140 arterial punctures, and in the postprotocol phase, we performed 112 punctures in 91 patients. Between the observation and postprotocol phases, patient demographics were similar; average sheath size was unchanged (sheaths over 6F 6% vs 8%, respectively, P = .55), and percentage of patients receiving heparin did not change significantly (76% vs, 86%, P = .08). No major complications occurred in either the observation or the postprotocol phases. While 24 minor complications occurred in the observation phase, only seven minor complications occurred in the postprotocol phase (17% vs 7%, P < .02). Closure device use decreased with protocol implementation (57% to 32%, P < .01), but closure device failures also decreased from 23% to 7% (P < .01). Process improvement, achieved by instituting a standardized percutaneous arterial closure protocol based on selective closure device use guided by sheath size, arterial calcification, and previous access scarring. Implementation of our protocol resulted in a decrease in the incidence of minor complications at the access site and refined patient selection for closure device use.
    Journal of vascular surgery: official publication, the Society for Vascular Surgery [and] International Society for Cardiovascular Surgery, North American Chapter 09/2008; 48(6):1481-8. · 3.52 Impact Factor
  • Article: Long-term results of combined common femoral endarterectomy and iliac stenting/stent grafting for occlusive disease.
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    ABSTRACT: Common femoral artery (CFA) endarterectomy with iliac stenting or stent grafting can be an alternative to traditional open surgery in patients with aortoiliac occlusive disease. We report the long-term outcomes of this approach. Patients undergoing CFA endarterectomy with simultaneous iliac stenting/stent grafting between 1997 and 2006 were retrospectively reviewed. Technical success, clinical and hemodynamic outcomes, and 5-year patency using life-table methodology were determined. Factors associated with reintervention and mortality were determined by logistic regression analysis. A total of 171 patients (mean age, 67 +/- 10 years; 38% female; 35% diabetic) underwent 193 CFA endarterectomies and iliac stent/stent grafting. Indications were rest pain (32%), tissue loss (22%), and claudication (46%). External iliac artery (EIA) lesions were present in 39%, and combined common iliac artery (CIA) and EIA lesions were seen in 61% of patients. Complete CIA/EIA occlusions were present in 41% of patients. Stent grafts were used in 41% of patients. Technical success occurred in 98% of patients. Clinical improvement was seen in 92% of patients. Mean ankle-brachial index increased from 0.38 +/- 0.32 to 0.72 +/- 0.24. Median length of stay was 2 days (range, 1-51 days). Thirty-day mortality was 2.3% and 5-year survival was 60%. Five-year primary, primary-assisted, and secondary patencies were 60%, 97%, and 98% respectively. Endovascular reintervention was required in 14% of patients; inflow surgical procedures were required in 10%. By logistic regression analysis, use of stent grafts compared with bare stents was associated with significantly higher primary patency (87% +/- 5% vs 53% +/- 7%; P < .01). Combined CFA endarterectomy with iliac intervention yield acceptable long-term results. The use of stent grafts compared with bare stents is associated with improved primary patency.
    Journal of vascular surgery: official publication, the Society for Vascular Surgery [and] International Society for Cardiovascular Surgery, North American Chapter 07/2008; 48(2):362-7. · 3.52 Impact Factor
  • Article: Hyperoncotic enhancement of fetal pulmonary growth after tracheal occlusion: an alveolar and capillary morphometric analysis.
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    ABSTRACT: Previous work has shown that intrapulmonary delivery of oncotic agents enhance overall lung growth after late gestational fetal tracheal occlusion (TO). This study was a post hoc analysis aimed at determining whether actual alveolar and capillary hyperplasias are maximized in this setting. Twenty-one near term fetal lambs were evenly divided into 4 groups: group I comprised sham-operated controls; group II had TO alone; and groups III and IV underwent TO and intratracheal infusion of equal amounts of either saline or 25% albumin, respectively. Approximately 2 weeks thereafter, their lungs were examined by detailed alveolar and capillary morphometry before birth. Statistical analysis included analysis of variance and the Bonferroni correction for multiple comparisons (P < .05). Total alveolar and capillary numbers, as well as total alveolar surface area, were significantly higher in group IV and lower in group I compared with all other groups, with no differences between groups II and III. Alveolar capillary load was normal in all groups. Intrapulmonary delivery of concentrated albumin safely enhances short-term alveolar and capillary hyperplasia in a late gestational model of fetal TO. This therapeutic concept may allow for TO to be effective and predictable when performed late in gestation.
    Journal of Pediatric Surgery 08/2006; 41(7):1214-8. · 1.45 Impact Factor
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    Article: Update in management of mesenteric ischemia.
    Robert-W Chang, John-B Chang, Walter-E Longo
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    ABSTRACT: Mesenteric ischemia disorders are precipitated by a circulation insufficiency event that deprives one or several abdominal organs of adequate respiration to meet metabolic demands. Although mesenteric ischemia occurs infrequently, the mortality rate is from 60% to 100%, depending on the source of obstruction. The successful outcome is dependent upon a high index of suspicion and prompt management. We briefly review the pathophysiology and presentation of the various ischemic entities and review the current state of the art in diagnosis and treatment. Despite advances in both diagnosis and treatment, prompt diagnosis and supportive care remain critical for successful outcome. New imaging techniques, endovascular therapy and emerging research may improve our approach to this deadly condition.
    World Journal of Gastroenterology 06/2006; 12(20):3243-7. · 2.47 Impact Factor
  • Article: Serial transverse enteroplasty enhances intestinal function in a model of short bowel syndrome.
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    ABSTRACT: OBJECTIVE/SUMMARY BACKGROUND DATA: Serial transverse enteroplasty (STEP) is a new intestinal lengthening procedure that has been shown to clinically increase bowel length. This study examined the impact of the STEP procedure upon intestinal function in a model of short bowel syndrome. Young pigs (n=10) had a reversed segment of bowel interposed to induce bowel dilatation. Five pigs underwent a 90% bowel resection with a STEP procedure on the remaining dilated bowel while 5 served as controls and had a 90% bowel resection without a STEP procedure. Determinations of nutritional status, absorptive capacity, and bacterial overgrowth were conducted 6 weeks after resection. Statistical comparisons were made by 2-sample t test (significance at P<0.05). The STEP procedure lengthened the bowel from 105.2+/-7.7 cm to 152.2+/-8.3 cm (P<0.01). The STEP animals showed improved weight retention compared with controls (mean, -0.5%+/-1.8% body weight versus -17.6%+/-1.5%, P<0.001). Intestinal carbohydrate absorption, as measured by d-Xylose absorption and fat absorptive capacity as measured by serum vitamin D and triglyceride levels, were increased in the STEP group versus controls. Serum citrulline, a marker of intestinal mucosal mass, was significantly elevated in the STEP pigs compared with controls. None of the STEP animals but 4 of 5 control animals were noted to have gram-negative bacterial overgrowth in the proximal bowel. STEP improves weight retention, nutritional status, intestinal absorptive capacity, and serum citrulline levels in a porcine short bowel model. A salutary effect upon bacterial overgrowth was also noted. These data support the use of this operation in short bowel syndrome.
    Annals of Surgery 02/2006; 243(2):223-8. · 7.49 Impact Factor
  • Article: Impact of AMICAR on hemorrhagic complications of ECMO: a ten-year review.
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    ABSTRACT: Preliminary studies have shown aminocaproic acid (AMICAR), an inhibitor of fibrinolysis, reduced the incidence of intracranial hemorrhage and significant surgical site bleeding in patients on extracorporeal membrane oxygenation (ECMO). The purpose of this analysis is to determine if these benefits remain when AMICAR is used in a large population. ECMO patients from a single pediatric institution, with routine use of AMICAR for "high-risk" patients, were evaluated retrospectively from 1991 to 2001. Data including diagnosis, duration of support, significant complications, and survival were recorded. These variables were compared with those of the Extracorporeal Life Support Organization (ELSO), an international ECMO registry, using a chi2 test. P less than.05 was deemed significant. ECMO was used 431 times during the 10-year study period. A total of 298 patients received AMICAR, most frequently for surgical procedures. The survival rate was not statistically different in the study group when compared with the ELSO Registry (P =.06). The rate of neonatal intracranial hemorrhage was not significantly different between the 2 groups (P =.133); however, the rate of surgical site bleeding was significantly reduced in the study population (P =.005). Decrease in surgical site bleeding was particularly evident in cardiac patients (P <.001). In this large experience, use of AMICAR for high-risk patients on ECMO did not appear to alter the rate of neonatal intracranial hemorrhage, but did significantly reduce the incidence of surgical site bleeding. AMICAR remains a valuable tool for the prevention of hemorrhage in patients undergoing operation prior to or while on ECMO.
    Journal of Pediatric Surgery 08/2003; 38(8):1212-6. · 1.45 Impact Factor