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Biomedical subjects

D B Walsh

Publications and source records attributed to D B Walsh.

At least 19 recordsLinked to original sources
PubMed1992

Pelvic blood flow following aortobifemoral bypass with proximal end-to-side anastomosis.

Nine patients with end-to-side aortobifemoral bypasses were studied in the first year after surgery using color duplex imaging to determine the source of pelvic blood flow. No patient had clinical evidence of postoperative pelvic ischemia. Six of nine patients were found to have occluded distal aortas by duplex studies performed at a mean of 4.4 months postoperatively (range 0.8-8.2 months). Of those six patients, postoperative duplex examination demonstrated two with no common or external iliac blood flow, two with bilateral retrograde external iliac flow, and two with unilateral retrograde external iliac flow. Of the three patients with patent distal aortas, two had no demonstrable external iliac blood flow, while the third had continued antegrade flow through one external iliac and retrograde flow through the other. Analysis of preoperative arteriograms failed to reveal accurate predictors of postoperative distal aortic patency or retrograde iliac blood flow. Despite the preoperative assumption that prograde common iliac artery blood was required to prevent pelvic ischemia, distal aortic patency was maintained in only three of nine patients. In the six patients with prograde iliac blood flow, no ischemic symptoms were present, including two patients with complete absence of antegrade aortic or retrograde external iliac blood flow. Our observations indicate that assumptions which underlie the decision to perform end-to-side aortic anastomoses are often not borne out in the months following aortobifemoral bypass.

Aged↗
PubMed1992

A blinded comparison of angiography, angioscopy, and duplex scanning in the intraoperative evaluation of in situ saphenous vein bypass grafts.

Angiography, angioscopy, and duplex scanning have each been advocated for intraoperative assessment of in situ saphenous vein grafts. We compared these three modalities during operation in a prospective, blinded study during the construction of 20 femoral-infragenicular in situ saphenous vein grafts. Each modality was used and interpreted by a surgeon blinded to the results of the other studies. Abnormalities requiring intervention were defined as (1) patent vein side branches, (2) residual valve cusps, and (3) anastomotic stenoses greater than 30%. Criteria, specific to the modality, corresponding to each category were prospectively defined. Fourteen residual valve cusps, 49 patent vein branches, and 6 anastomotic stenoses were suggested by at least one modality. Nine residual valve cusps, 32 patent vein branches, and no anastomotic stenoses were actually found (and corrected) by direct inspection. Sensitivity of detecting patent side branches for angiography, duplex scanning, and angioscopy was 44%, 12%, and 66%, respectively. Both angiography and angioscopy were significantly more sensitive than duplex scanning for detection of unligated side branches (p less than 0.01). Sensitivity of detecting residual valve cusps was 22% (angiography), 11% (duplex scanning), and 100% (angioscopy). Angioscopy was significantly more sensitive than either duplex scanning or angiography in detection of residual valve cusps (p less than 0.01). Since no anastomotic stenoses were confirmed, the false-positive rates for stenosis detection were 20% for angiography, 10% for duplex scanning, and 0% for angioscopy. Time requirement was 17 to 20 minutes and did not differ among the three modalities. No stenosis or arteriovenous fistula has been detected in any graft by postoperative duplex surveillance (mean, 10-month follow-up).(ABSTRACT TRUNCATED AT 250 WORDS)

Anastomosis, Surgical↗
PubMed1992

Current use of inferior vena cava filters.

To study possible changes in the clinical use of inferior vena cava (IVC) filters caused by the introduction of percutaneous delivery systems, we reviewed all patients who underwent placement of IVC filters at our institution from 1988 to 1991. Eighty-four patients (52 men and 32 women) ranging in age from 18 to 90 years (mean 67 years) were identified. Filters were required because of contraindications to anticogulation in 64% anticoagulation failure in 25%, and preoperative prophylaxis in 11% of patients. The underlying disease was lower extremity deep vein thrombosis in 50% and pulmonary embolism in 45% of patients. Five percent of patients received prophylactic filters without documented thromboembolism. All filters were placed percutaneously by interventional radiologists, 77 through the common femoral vein and 7 through the internal jugular vein. Three types of filters were used. One procedure-related death occurred because of acute IVC occlusion. Fatal pulmonary embolism within 48 hours after filter placement was documented in one patient and suspected in one late death. No other clinically apparent pulmonary embolism or leg swelling occurred after filter placement. Minor complications related to filter placement occurred in 13 patients, but none required operative intervention. Analysis of complication rates of the three filter types was precluded by the small sample size. After a mean follow-up of 11 months, 42 patients (50%) had died of malignancy (n = 25), multisystem organ failure (MSOF; n = 7), cardiovascular events (n = 4), recurrent pulmonary embolism (n = 2), cerebrovascular events (n = 4), or an unknown cause (n = 1). Twenty-three patients (27%) died before hospital discharge.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1992

Axillofemoral bypass: outcome and hemodynamic results in high-risk patients.

Aortobifemoral bypass (AoFB) is the preferred method to provide lower extremity inflow. To determine whether axillofemoral bypass (AxFB) is an acceptable alternative for high-risk patients, we reviewed our results with these two operations. Between 1985 and 1990, 29 axillobifemoral and 5 axillounifemoral bypass procedures were performed preferentially because of severe associated medical illness in patients with severe aortoiliac occlusive disease. During the same interval, 107 patients received an AoFB for pure aortoiliac occlusive disease. Nearly all patients having AxFB and AoFB were heavy smokers, and the two groups had similar rates of hypertension and angina. However, other major risk factors were more frequently found in patients undergoing AxFB. Limb-threatening ischemia was more frequent and femoral artery occlusive disease was more severe in patients having AxFB. Anastomosis to the deep femoral arteries and concomitant infrainguinal bypass were more likely to be required in patients who had AxFB. Life-table patient survival at 3 years was 35% for AxFB versus 91% for AoFB (p less than 0.001). Primary patency at 3 years was 63% for AxFB versus 85% for AoFB (p = 0.032). Secondary patency was 74% for AxFB versus 94% for AoFB (p less than 0.001). However, all revised grafts in both groups were patent at 36 months, and only one revised AxFB graft was an ultimate failure. Limb salvage at 3 years was 76% for AxFB versus 97% for AoFB (p = 0.065). Nineteen of the 22 patients with AxFB who died during follow-up died with patent grafts. Hemodynamic performance of AxFB and AoFB were compared. Mean preoperative ankle-brachial index was higher in AoFB (0.50) than AxFB (0.38, p less than 0.001), but postoperative ankle-brachial index was much higher after AoFB (0.83) than AxFB (0.57, p less than 0.001). Even after adjustment for severity of outflow disease, postoperative ankle-brachial index was much better after AoFB than AxFB. Axillofemoral bypass was performed in older higher risk patients with more severe ischemia than those in the AoFB group. Hemodynamic performance was inferior and graft failure more common after AxFB. However, AxFB provided limb salvage in all but 2 of 22 patients who have died, and no survivor has had amputation because of graft failure. Axillofemoral bypass is an acceptable but hemodynamically inferior alternative to AoFB in properly selected high-risk patients with critical lower extremity ischemia who would likely not tolerate the more durable AoFB.

Adult↗
PubMed1992

An unusual case of intermittent venous obstruction of the upper extremity.

The axillary vein can be subject to intermittent obstruction from numerous anatomic structures such as the pectoralis minor and the scalenus anterior muscles. The diagnosis can be readily made on history and physical examination of the upper extremity, but it can be difficult to confirm by routine venogram done with the arm in the standard position at the side with full extension at the antecubital fossa. Positional venography with the arm fully abducted and flexion of that antecubital fossa allows for better definition of this extrinsic compression. In the case presented, a fascial band arising from the medial head of the biceps was compressing the axillary vein and was suspected on history and physical examination; it was confirmed with positional venography as noted. As in this case, it is important to make the diagnosis early, before thrombosis of the vein occurs, to minimize the associated morbidity. Transaxillary exploration was performed with excision of the band and complete resolution of the symptoms. Subsequent noninvasive studies were performed that showed complete resolution of the extrinsic axillary vein compression. Having a high suspicion of intermittent venous obstruction with early diagnosis and surgical correction of any extrinsic compression are the keys to a successful outcome in these patients.

Adult↗
PubMed1991

Lack of diameter effect on short-term patency of size-matched Dacron aortobifemoral grafts.

This study examined the relationship between graft diameter and subsequent patency in 79 patients who received Dacron aortobifemoral bypass grafts for aortoiliac occlusive disease between 1985 and 1989. Sixty-five percent of these patients were men, 25% were diabetic, and 94% were smokers, with an average age of 62 years. Patients were followed for a mean interval of 24 months. Life-table survival was 92% at 3 years. All surviving patients showed "significant" postoperative improvement by use of Society for Vascular Surgery/International Society for Cardiovascular Surgery combined clinical and vascular laboratory criteria. There were three early and five late graft thromboses. Primary and secondary life-table patencies were 85% and 92%, respectively, at 3 years. Dacron bifurcation grafts were selected to match the size of native arteries. Patients receiving small diameter grafts, defined as 12 mm (n = 9) and 14 mm (n = 39), were compared with patients receiving large diameter grafts of 16 mm (n = 26) and 18 mm (n = 5). Small diameter grafts were more likely to be used in women (p less than 0.01), but patient groups were otherwise comparable with respect to age, smoking history, diabetes, outflow status, operative indications, type of proximal anastomosis (end-to-end or end-to-side), location of distal anastomosis (common femoral vs deep femoral), type of graft construction (knitted vs woven), and functional result. Graft diameter did not influence life-table patency, which was 84% for small and 87% for large diameter grafts at 3 years (p = 0.74). Furthermore, none of the other variables listed above influenced graft patency.(ABSTRACT TRUNCATED AT 250 WORDS)

Aorta, Abdominal↗
PubMed1991

The natural history of superficial femoral artery stenoses.

Since the natural history of specific superficial femoral artery stenoses is not known, we examined progression rates of superficial femoral artery stenoses in 45 lower extremities found when arteriograms were obtained of 38 patients for symptomatic atherosclerotic disease in the opposite leg or abdomen. These initial superficial femoral artery arteriograms were compared with later arteriograms in 25 limbs, duplex scans in 27 limbs, and both modalities in 7 limbs. After a mean interval of 37 months, most superficial femoral artery stenoses (72%) did not progress. However, 12 superficial femoral artery stenoses progressed (28%; mean follow-up, 37 months, including 7 that occluded (17%). Superficial femoral artery stenoses progressed among patients who complained of symptom progression at a rate faster than that among asymptomatic patients (15.6%/year vs 3%/year; p = 0.006). Superficial femoral artery lesions also progressed more rapidly among patients whose contralateral superficial femoral artery was occluded (10%/year vs 1.6%/year; p = 0.04). By multivariate regression analysis, symptom progression and smoking history were predictive of superficial femoral artery stenosis progression. In the seven patients whose superficial femoral artery stenoses progressed to occlusion, the average rate of stenosis progression was 12%/year (maximum predicted rate, 30% per year by 95% confidence limit). These results indicate that superficial femoral artery stenoses usually progress with synchronous symptomatic deterioration. Other than symptom progression, only cumulative smoking history and contralateral superficial femoral artery occlusion could be associated with superficial femoral artery stenosis progression in this small series.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1991

Duplex ultrasonography in the diagnosis of celiac and mesenteric artery occlusive disease.

Duplex ultrasound criteria for the diagnosis of celiac and superior mesenteric artery (SMA) occlusive disease have not been well defined. We performed a blinded retrospective comparison of mesenteric duplex data with arteriography in 24 consecutive patients who underwent both studies. Arteriography revealed that eight superior mesenteric arteries were normal; five were minimally stenotic; eight had stenoses greater than or equal to 50%, and three were occluded. Nine celiac arteries were normal or minimally stenotic; 12 had stenoses greater than or equal to 50%, and three were occluded. Duplex scans were obtained after an overnight fast. In normal superior mesenteric arteries, peak systolic velocity (PSV) was 134 +/- 18 cm/sec and end-diastolic velocity (EDV) was 24 +/- 4 cm/sec. Superior mesenteric artery PSV in patients with minimal or no stenosis (171 +/- 22 cm/sec) was less than PSV in patients with severe (greater than 50%) stenosis (299 +/- 40 cm/sec, p = 0.006), and less than PSV in patients with patent superior mesenteric arteries who underwent revascularization (366 +/- 86 cm/sec, p = 0.017). Similarly, EDV was elevated in superior mesenteric arteries with severe stenosis (78 +/- 11 cm/sec, p = 0.001) and in patients who underwent revascularization (111 +/- 19 cm/sec, p less than 0.001) compared to those with less than 50% stenosis (30 +/- 6 cm/sec, p = 0.001). An EDV greater than 45 cm/sec was the best indicator of severe stenosis (sensitivity, 1.0; specificity, 0.92). Peak systolic velocity greater than 300 cm/sec was less sensitive (0.63), but highly specific (1.0) for severe superior mesenteric artery stenosis.(ABSTRACT TRUNCATED AT 250 WORDS)

Arterial Occlusive Diseases↗
PubMed1991

The role of calcium ions and calcium channel entry blockers in experimental ischemia-reperfusion-induced liver injury.

Verapamil administered before treatment, but not after treatment, had a beneficial effect on a 90-minute warm ischemia-reperfusion rat liver injury model. The possible activation of proteases converting the xanthine dehydrogenase to xanthine oxidase, the significant mitochondrial calcium loading during the ischemic period, and the potentiation of calcium and oxygen-derived free radicals to promote injury to mitochondria are mechanisms supported by this study, based on both histologic observations and on the pattern of enzyme leak after the acute ischemic event.

Alanine Transaminase↗
PubMed1991

The effect of ibuprofen on cardiac performance during abdominal aortic cross-clamping.

Decreased cardiac output and increased plasma thromboxane have been observed during aortic cross-clamping under general anesthesia. Amelioration of these changes has been reported by preoperative administration of cyclooxygenase inhibitors, but heterogeneity in patients' intravascular volume status has confounded analysis of the drugs' effects in previous studies. We studied hemodynamic conditions in 24 volume-loaded (pulmonary capillary wedge pressure greater than 10 mm Hg) patients undergoing abdominal aortic aneurysm repair under general plus epidural anesthesia, after preoperative double-blind administration of either ibuprofen 800 mg (n = 12) or placebo (n = 12). The hemodynamic response to aortic cross-clamping was similar in both groups. Pulse and mean arterial pressure remained unchanged; cardiac index decreased after aortic cross-clamping from 2.4 +/- 0.1 (mean +/- standard error of the mean [SEM]) to 2.1 +/- 0.1 1/min/m2 in the ibuprofen group and from 2.5 +/- 0.1 to 2.3 +/- 0.2 1/min/m2 in the placebo group (p less than 0.01 versus preclamp values in both groups, multivariate analysis of variance [MANOVA]), but improved after declamping. Both left and right ventricular stroke work indexes followed a similar pattern. Plasma 6-keto prostaglandin Fl alpha (6-k-PGF1 alpha) increased transiently from a baseline level of 304 +/- 44 to 2083 +/- 698 pg/ml plasma in mixed venous blood 30 minutes after incision in the placebo group (p less than 0.05), but no other significant change in plasma 6-keto prostaglandin Fl alpha or in thromboxane B2 occurred in either group at any other time.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1990

Intragraft drug infusion as an adjunct to balloon catheter thrombectomy for salvage of thrombosed infragenicular vein grafts: a preliminary report.

Early infragenicular vein graft thrombosis is associated with poor secondary patency, particularly when no correctable defect is identified. We have attempted to improve patency of thrombosed vein grafts by direct infusion of vasodilator and anticoagulant drugs after surgical thrombectomy. Among 212 infragenicular vein grafts, 16 (7.5%) required thrombectomy within 30 days of surgery (14 in situ saphenous vein, 1 composite vein, and 1 cephalic vein graft). Causes for failure were corrected in four (graft twist, intimal tear, suture failure, and external compression), resulting in prolonged patency. No cause for failure was apparent in the 12 remaining grafts after balloon catheter thrombectomy and arteriography. Two of these grafts occluded within 10 days despite multiple attempts at vein patch angioplasty, distal graft extension, and repeat thrombectomy with systemic anticoagulation. In the remaining 10 grafts, a small polyethylene catheter was placed in a proximal vein branch for direct intragraft drug infusion. Heparin (10 units/min) and nitroglycerin (50 micrograms/min) were the agents infused most frequently, for a mean duration of 52 hours after thrombectomy. Of these 10 infused grafts, 8 remained patent during a mean 17-month follow-up (range, 6 to 38 months). This was accomplished despite previous and repeated failures of thrombectomy and systemic anticoagulation in seven of these eight grafts. Two infused grafts rethrombosed within 30 days of infusion, resulting in amputation. No catheter-related complications occurred. Increased thrombogenicity, intimal injury, and spasm after balloon catheter thrombectomy may contribute to vein graft rethrombosis in the absence of technical defects. Direct intragraft infusion of nitroglycerin and heparin contributed to prolonged salvage of 80% of thrombosed vein grafts in this preliminary experience.

Aged↗
PubMed1990

The effect of glucose infusion on survival after acute mesenteric ischemia/reperfusion.

Perfusion of ischemic tissue with glucose has been shown to be deleterious to heart, spinal cord, and kidney. Observations that glucagon improves survival after acute mesenteric ischemia, however, suggest that hyperglycemia may not be deleterious during bowel ischemia. This experiment examined the effect of glucose infusion on survival in an established rat model of acute mesenteric ischemia. The superior (cranial) mesenteric artery (SMA) was occluded for 85 min in 36 anesthetized Sprague-Dawley rats. Animals were randomized to receive 5% glucose in normal saline (n = 15; 16.5 mL/kg.min iv), normal saline alone (n = 13; 16.4 mL/kg.min iv), or no intravenous fluid (n = 8). Ninety-minute intravenous infusions were initiated 10 min after SMA occlusion. Survival to 48 h was 47% in glucose-saline-treated rats, 31% in saline-only-treated rats, and 12.5% in control rats. These results demonstrate no deleterious effect of glucose infusion on mortality after acute mesenteric ischemia in this model.

Animals↗
PubMed1990

Oxygen-derived free radicals in hepatic ischemia and reperfusion injury in the rat.

We have previously described a chronic, in vivo biochemical and histologic model of ischemia and reperfusion injury and wished to test the ability of superoxide dismutase, catalase and allopurinol to protect against the hepatocellular injury demonstrated by this model. Xanthine oxidase inhibitors given preoperatively produced a significant hepatocellular protective effect when compared with a comparable insult delivered to a cohort of control rats. The protection given seemed greater than that produced by pretreatment with free radical scavengers. Possible mechanisms for this observation are discussed. Investigations combining free radical scavengers with xanthine oxidase inhibitors may further define protection for warm hepatic ischemia and reperfusion injury.

Allopurinol↗
PubMed1990

Variables that affect the expansion rate and outcome of small abdominal aortic aneurysms.

Seventy-three patients with small (less than 6 cm in diameter) abdominal aortic aneurysms (AAAs) were selected for nonoperative management and followed up with sequential ultrasound size measurements. Fifty-four men and 19 women, 51 to 89 years of age (mean 70 years), had an initial mean AAA size of 4.1 cm (anteroposterior) x 4.3 cm (lateral) diameter, with a calculated elliptic cross-sectional area of 14.3 cm2. After a mean of 37 months of follow-up, AAA area increased at a mean rate of 20% per year (3 cm2 yr; 0.4 to 0.5 cm/yr diameter). Expansion rate was not affected by initial aneurysm size. During follow-up, only 3 patients (4%) required urgent operation (1 died), 26 patients (36%) died of non-AAA causes, and 26 patients (36%) underwent elective AAA repair because of progressive size increase (1 died). Elective operations were performed at the rate of 10% per year, when mean AAA size had increased to 22 cm2 (5.1 cm in diameter). Multiple regression analysis of clinical parameters available at presentation indicated that subsequent elective AAA repair was predicted by younger age at diagnosis and larger initial aneurysm size. As anticipated, patients who underwent surgery had more rapid aneurysm expansion (5.3 cm2/yr) compared with patients who did not undergo surgery (1.6 cm2/yr; p less than 0.05). This difference was caused by more rapid expansion during later follow-up intervals among patients selected for operation and was not predicted by the change in aneurysm size observed during initial ultrasonographic follow-up. Final aneurysm size was predicted by initial size, duration of follow-up, and both systolic and diastolic pressure.(ABSTRACT TRUNCATED AT 250 WORDS)

Actuarial Analysis↗
PubMed1989

Limb salvage despite extensive tissue loss. Free tissue transfer combined with distal revascularization.

Extensive lower-extremity tissue loss may preclude limb salvage despite successful arterial reconstruction. We attempted to avoid limb loss in such patients by combining arterial bypass with microvascular free tissue transfer. Fourteen patient (12 diabetic), 33 to 74 years of age, presented with extensive tissue loss in 15 lower extremities, exposing bone or tendon on the heel, ankle, lower part of the leg, or hindfoot. Mean ulcer size was 5 X 8 cm. Four patients had had previous contralateral below-knee amputations. Femorodistal (seven), popliteal-distal (three), or femoropopliteal (four) bypass, or tibial angioplasty (one), was performed to provide sufficient inflow for free tissue transfer. Serratus anterior, scapular, latissimus dorsi, rectus abdominis, gracilis, ulnar, or temporalis free flaps were used. One free flap failed due to venous thrombosis and was corrected with a second flap. Limb salvage was achieved in 14 (93%) of 15 limbs during a mean follow-up of 24 months. The single amputation occurred due to severe foot ischemia in a patient whose femorodistal bypass remained patent only to the viable free flap. The remaining 13 patients (14 limbs) became ambulatory, including those with free flaps to weight-bearing regions.

Adult↗