Biomedical subjects
M R Gaspar
Publications and source records attributed to M R Gaspar.
Extrahepatic portal vein aneurysm: report of a case treated by thrombectomy and aneurysmorrhaphy.
Extrahepatic portal vein aneurysm is a rare condition with only 15 cases before ours being reported in the English literature. The etiology is thought to be congenital, secondary to portal hypertension or associated with abnormal weakness of the vein wall. It often presents in conjunction with major gastrointestinal bleeding, but may occur with minimal or no symptoms. Diagnosis is made with color duplex ultrasound, computed tomographic scan, venous phase mesenteric angiography, magnetic resonance imaging, or splenoportography. Thrombosis, rupture, and pressure effects are the major complications of portal vein aneurysm. Shunting procedures are recommended in cases with portal hypertension secondary to liver disease. We report the first case treated by thrombectomy and aneurysmorrhaphy with a successful 10 year follow-up. This procedure should be considered to preserve portal vein flow when portal hypertension is absent or is secondary to the aneurysm itself.
Carotid endarterectomy.
A technique for carotid endarterectomy done under general anesthesia features the routine use of a straight shunt, precise removal of all plaque and shreds of media, and routine completion angiography done as a means of quality control.
Selective use of arteriography in the assessment of aortic aneurysm repair.
Routine preoperative arteriography is advocated by many vascular surgeons before abdominal aortic aneurysm repair. We have used a selective approach based on the facts that arteriography is expensive, time-consuming, potentially hazardous, and often unwarranted. Based on preoperative indications, arteriography was used selectively in 41 of 100 consecutive patients prior to abdominal aortic aneurysmectomy. Many patients had more than one indication. A total of 82 specific indications were recognized. The most frequent indications were diminished lower extremity pulses (24), claudication (20), severe coronary artery disease (11), cerebrovascular disease (7), prior arterial reconstruction (8), hypertension in patients 60 years of age or less (5), evidence of other aneurysms (4), major renal anomaly (1), blue toe syndrome (1), and thoracic aneurysm (1). The 41 arteriograms produced 125 specific arteriographic abnormalities with an average of three per study. The most arteriographic abnormalities were in those patients with claudication and the least for those with hypertension. The arteriogram revealed information that would not have been obvious at operation, nor would it have led to operative procedure modification in only 10 patients. In the 59 patients not having arteriography, three had intraoperative findings which demanded a modification of the operative procedure. Thus, in only 13 patients was arteriography definitely useful. Presumably it was not indicated in the other 87. By comparing the cases in which the operation was modified with the presence of a specific indication, we have developed a predictability index as a guide for performing arteriography. Multiple indications increased the likelihood of operation modification only if four or more indications were present.
An effective treatment protocol for intraarterial drug injection.
Between 1972 and 1988, 48 patients with extremity ischemia after an intraarterial drug injection were treated with the following protocol: heparin, dextran 40, dexamethasone, elevation, and early mobilization of the extremity. A tissue ischemia score, derived by assessing the color, capillary refill, sensory function, and temperature of the extremity, was used to assess the ischemic injury. Each sign was scored either normal = 0 or abnormal = 1; then summed to provide the tissue ischemia score (range, 0 to 4). Twenty-four (50%) patients had an extremity tissue ischemia score less than or equal to 2. After treatment 22 of the 24 patients had a normal extremity, and 2 required limited digital amputations. In this group, outcome was comparable regardless of the time interval from intraarterial drug injection to treatment. Ten of 24 (50%) patients with an extremity tissue ischemia score greater than 2 had a normal extremity, 3 had a functional deficit, and 11 required digital amputations. Twelve of the 24 patients were treated within 24 hours and had a significantly superior outcome when compared to the 12 who were treated more than 24 hours after intraarterial drug injection (p less than 0.001, Fisher's exact test). The tissue ischemia score is a useful predictor of extremity outcome in patients with intraarterial drug injection. The outlined treatment protocol is effective in minimizing tissue injury caused by intraarterial drug injection. Institution of treatment within 24 hours of intraarterial drug injection is particularly important in patients who manifest severe ischemia.
Abdominal aortic and multiple iliac aneurysms associated with crossed-fused ectopia of the kidney: a case report and review.
We report the first case of an infrarenal abdominal aortic aneurysm associated with crossed-fused ectopia of the kidney. This is the second most common fusion defect of the kidney with an incidence in the general population of 1 in 1000. The different types of crossed renal ectopia with and without fusion are described. The renal artery anomalies associated with crossed renal ectopia are emphasized. Abdominal ultrasonography or CT scanning must be used to uncover renal anomalies before surgery so that a selective preoperative aortogram can be obtained to determine the location of the arterial supply to the kidneys.
Devastating distal arterial trauma and continuous intraarterial infusion of tolazoline.
Trauma due to motor vehicles accident and urban violence have made distal arterial reconstruction an increasingly important part of the surgeon's work. During the 20 month period from October 1980 to May 1982, 13 patients with below the knee and 2 patients with forearm trauma had nonviable extremities despite fastidious vascular and orthopedic reconstruction. A continuous intraarterial infusion of tolazoline into the femoral or brachial arteries restored vascular perfusion and viability in 13 of 15 patients (87 percent), with eventual limb salvage in 67 percent. Seven of 15 patients (47 percent) had transient systemic hypertension. There was no mortality. There exists in patients with these catastrophic injuries a local low-flow state due to a combination of distal arterial spasm and venous outflow obstruction. Tolazoline, a peripheral alpha-adrenergic blocking agent, increases blood flow, albeit nonnutritionally, and thus theoretically prevents thrombosis due to stasis in the repaired distal vessel. When limb loss seems inevitable, a trial of intraarterial tolazoline is justified.
Prolene sutures are not a significant factor in anastomotic false aneurysms.
Anastomotic false aneurysms have been a significant complication in vascular surgery, and the sutures used have been a major cause. Monofilament sutures have been indicated as contributing to the formation of false aneurysm. However, most of the monofilament sutures operative in the formation of false aneurysms have been made of polyethylene. Polypropylene, although significantly different from polyethylene, has been associated and possibly confused with it. Very few anastomotic aneurysms have resulted from breakage of polypropylene sutures. In this series of 2,400 vascular anastomoses in which polypropylene sutures were used, there were 10 false aneurysms; however, only one resulted from suture failure. In that patient, two Dacron grafts were anastomosed with 5-0 polypropylene suture. Polypropylene is a satisfactory and safe suture material for vascular anastomoses. It does not fragment or break easily when properly handled, and therefore is not a principal cause of false aneurysms.
Routine aortography before abdominal aortic aneurysmectomy. A prospective study.
Routine preoperative arteriography was studied prospectively in 104 patients with abdominal aortic aneurysms. The patients were from the private practice of 11 vascular surgeons. Information regarding patient clinical status was gathered and compared with aortographic and intraoperative findings. Special attention was focused on the question of operation modification as dictated by aortographic findings. The surgeons were further asked whether the information gained from surgical exploration was equal to that obtained from arteriography. It is concluded that because of low yield of benefit, economic considerations, time delay, and minor but distinct risks of the procedure, arteriography should be used selectively rather than routinely in such patients.
David M. Hume Memorial Lecture. The surgeon and the pilot.
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Arterial embolism and thrombosis.
An effort should be made to differentiate between acute arterial embolism and acute arterial thrombosis. Most patients seen early with acute arterial embolism and a viable extremity should be heparinized and operated upon as soon as possible. Patients with acute arterial thrombosis should be treated with heparin and possibly streptokinase and not operated upon urgently. That group of patients in whom the diagnosis is in doubt and who have a viable extremity should be heparinized and have arterial exploration only if their general condition is satisfactory for an operation. Patients with a nonviable extremity should have an amputation as soon as their general condition permits. One important implication in the modern era of the management of peripheral arterial embolectomy is the requirement that the surgeon dealing with the embolus identify its source and institute appropriate treatment, whether it be replacement of a cardiac valve or removal of a proximal arterial aneurysm.
Femoral-popliteal-tibial reconstruction.
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Aortoiliac and aortoiliofemoral reconstruction.
In general, aortoiliac and aortoiliofemoral reconstruction when properly selected and properly performed is one of the most gratifying peripheral vascular procedures. The mortality is reasonably low in spite of the fact that the patients operated upon have generalized arteriosclerosis, including coronary artery diseases. The precise procedure selected depends upon many factors having to do with the patient's general condition, body habitus, and artery condition. Although thromboendarterectomy always will have a place, it has been superseded largely by bypass grafts because grafting is an easier operation. As yet, however, bypass grafts have not been shown to have a clear-cut superiority in long-term patency.
Basic techniques in arterial surgery.
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Alternate routes for bypass grafts.
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Renovascular hypertension.
If only 1 per cent of the 23 million hypertensive patients in the United States had renovascular hypertension, many patients would be denied the chance for cure. Strong clinical suspicion plus arteriography are the mainstays of diagnosis. Positive renal vein renin studies provide the best preoperative evidence for cure by operation, but many patients with negative studies benefit from operation. Surgeons have been ingenious in devising methods of renal revascularization. Those we prefer are listed in Table 12-6. In most cases it should be possible to revascularize the kidney successfully without resorting to nephrectomy. About nine out of ten patients should benefit from operation; of these, some should be cured and others improved even though antihypertensive medication might be required.