Pharmacotherapy to improve outcomes in infrainguinal bypass graft surgery: a review of current treatment strategies.
ABSTRACT A total of 12,000 infrainguinal bypass grafts are performed annually in the United Kingdom, with outcomes suboptimal: 20% of above-knee vein grafts require intervention by 3 years. Transatlantic Inter-Society Consensus (TASC) guidelines exist on pharmacological management of peripheral vascular disease patients, however, little is recommended regarding optimum pharmacological management following revascularization to improve graft patency. The current recommendation is that all patients are on an antiplatelet agent following bypass grafting, the only intervention with significant evidence supporting use. This article will review pharmacological strategies aimed at improving the survival of infrainguinal vein grafts and the current evidence base for their use.
Conference Paper: A new readout structure for radiation silicon strip detectors[Show abstract] [Hide abstract]
ABSTRACT: Both silicon strip detectors and CCD detectors are commonly used to detect elementary particles in high energy physics. Strip detectors have a large time resolution but are difficult to read out because of the large number of bondings. CCD detectors have an elegant readout scheme but a low readout duty cycle. This paper presents a new method for reading out microstrip detectors with the aid of CCD's, making use of junction CCD's and their unique input structure. It yields a large time resolution, consumes little chip area and overcomes the problems of the wiring and amplification of single strip detectors. Initial experiments have demonstrated the feasibility of this method.Electron Devices Meeting, 1983 International; 02/1983
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ABSTRACT: To compare the effects of prostaglandin E1 (PGEl) versus placebo on blood flow rate in coronary artery bypass grafts. A prospective, randomized, double-blinded study. A teaching hospital. Forty-six patients with stable angina scheduled for isolated elective OPCAB were recruited and randomized into group PGE1 and group placebo. Following randomization, the patients in the PGE1 group (Group PGE1, n = 23) received a continuous intravenous infusion of PGEl (10 ng/kg/min) after endotracheal intubation and the placebo group (Group placebo, n = 23) received the same volume of normal saline. The infusion administration was removed after leaving the intensive care unit. The grafts' blood flow rate was measured with a transit time flowmeter at 10 minutes and 30 minutes after coronary artery grafting. The hemodynamic parameters, including mean arterial pressure (MAP), heart rate, and SvO2, VO2I, DO2I, ERO2 monitored by a pulmonary artery catheter, were recorded. The blood flow of the saphenous vein grafts was significantly higher in the PGE1 group than the placebo group at both 10 and 30 minutes after coronary artery grafting. At the 10-minute mark, the graft flow was 54.9±31.4 mL/min versus 47.3 ±24.6 mL/min in venous nonsequential grafts to the left coronary artery for group PGE1 and placebo (p = 0.000). Corresponding values at 30 minutes were 60.1±27.8 mL/min versus 48.4±26.3 mL/min (p = 0.002). In the venous non-sequential grafts to the right coronary artery, a tendency of blood flow also was found to be higher in the PGE1 group than in the placebo group at 10-minutes (52.7±29.4 mL/min versus 49.3 ±23.8 mL/min, p = 0.048) and the 30-minutes (58.6±26.5 mL/min, 50.9±25.9 mL/min, p = 0.037). The blood flow rate of the left internal mammary artery (LIMA) grafts in group PGE1 was higher than that in the placebo group but did not reach statistical significance. The VO2I, DO2I, and ERO2 in the 2 groups at the 2 time points did not reach statistical significance. The cardiac index (CI) in group PGE1 was higher than that of the placebo group at T3 and T4 (p = 0.035 and p = 0.012, respectively). The lactate (LAC) at the end of the operation (T2), 4 hours after the operation (T3), and 24 hours after operation (T4) in the placebo group were higher than that of group PGE1 (p = 0.023, p = 0.015, and p = 0.043, respectively). The oxygenation saturation of the mixed venous blood (SvO2) in the 2 groups was decreased but without significant difference. PGE1 significantly increases the flow rate in anastomosed saphenous vein grafts, and its beneficial effects on hemodynamics and oxygen metabolism can be observed.Journal of cardiothoracic and vascular anesthesia 09/2013; · 1.06 Impact Factor
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ABSTRACT: To determine if intraoperative distal graft end-diastolic velocity (EDV) using completion duplex ultrasound (CDU) predicts patency of crural bypass in patients with critical limb ischemia (CLI). Records of 116 non-consecutive patients who underwent crural revascularization with vein conduit and CDU between 1998 and 2008 were reviewed. Bypass grafts were performed for rest pain (34%) or tissue loss (66%), while 56% of the reported cases were categorized as "disadvantaged" because of compromised vein quality or diseased arterial outflow. A 10-MHz low-profile transducer was used to image the entire bypass at case completion. Technical adequacy of the grafts was verified by absence of retained valves, arteriovenous fistulas, or localized velocity increases and presence of bypass-dependent distal pulses. Modified Rutherford scores were calculated as surrogate markers of runoff resistance and compared to distal graft EDV. The primary study end point was graft patency during a 1-year posttreatment period. Patency rates were determined using Kaplan-Meier life table methodology and compared using the log-rank test. Predictors of graft patency were determined by Cox proportional hazards. Primary, primary-assisted, and secondary patency for all crural bypasses were 62%, 66%, and 70% at 1 year, respectively. When stratified by tertiles of distal graft EDV (0 - <5 cm/s, 5-15 cm/s, >15 cm/s), 1-year primary patency rates were 32%, 64%, and 84% (P = .001). Low (0 - < 5 cm/s) distal graft EDV (hazard ratio [HR], 3.3 confidence interval [CI], 1.74-6.41; P < .001), poor-quality conduit (HR, 2.5; CI, 1.19-5.21; P = .016), age <70 (HR, 2.08; CI, 1.06-4.00; P = .031), and lack of statin use (HR, 2.04; CI, 1.04-4.00; P = .038) were independent predictors of graft failure. While the modified Rutherford score correlated with distal graft EDV (P = .05), it was not an independent predictor of patency (P = .58). Predictors of low EDV (<5 cm/s) included single-vessel runoff (odds ratio [OR], 3.33; CI, 1.14-9.71; P = .027), poor conduit (OR, 2.94; CI, 1.16-7.41; P = 0.024), and diabetes (OR, 2.86; CI, 1.14-7.21; P = .025). Distal graft EDV predicts crural vein graft patency in patients with CLI. Grafts with EDV <5 cm/s remain at high risk for early failure. The impacts on patency of statins, age, and poor-quality conduit are, again, confirmed. These results highlight the value of EDV using intraoperative CDU for anticipating and, possibly, improving results of open crural revascularization.Journal of vascular surgery: official publication, the Society for Vascular Surgery [and] International Society for Cardiovascular Surgery, North American Chapter 08/2011; 54(4):1006-10. · 2.98 Impact Factor