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Biomedical subjects

J M Guernsey

Publications and source records attributed to J M Guernsey.

10 recordsLinked to original sources

Dipyridamole thallium scanning in the evaluation of coronary artery disease in elective abdominal aortic surgery.

Dipyridamole thallium scanning was routinely performed on 68 consecutive patients who presented for elective aortic surgery. All 68 patients were judged by clinical assessment to be at low risk for perioperative cardiac complications. In addition, 42 of 68 patients had a history of myocardial infarction, stable angina, or abnormal echocardiographic findings (group 1). Twenty-six of 68 patients did not have a history of myocardial infarction, angina, or abnormal echocardiographic findings (group 2). In group 1, 34 of 4 patients had positive results on dipyridamole thallium scanning, and 15 of these patients were found to have critical coronary artery disease on subsequent cardiac catheterization; nine underwent immediate coronary artery bypass grafting, and six had their coronary artery disease treated medically and their vascular operations cancelled. The remaining 27 patients in group 1 underwent elective operations, with six (22%) of 27 sustaining postoperative cardiac complications. None of the group 2 patients was found to have critical coronary artery disease. All patients in group 2 underwent aortic operation without cardiac complication. Routine dipyridamole thallium scanning detected a 22% (15 of 68) incidence of critical coronary artery disease overall. There was a 36% (15 of 42) incidence of critical coronary artery disease in group 1 patients vs 0% in group 2 patients (95% confidence interval, 21% to 50%). We conclude that the use of dipyridamole thallium scanning in low-risk patients for cardiac screening prior to elective aortic operations is beneficial in selected patients who have a history of myocardial infarction, angina, or abnormal echocardiographic findings, but is not necessary in patients with no history of coronary artery disease.

Aged

Peripheral nerve conduction abnormalities in lower extremity ischemia: the effects of revascularization.

Peripheral nerve conduction studies were performed on 32 limbs in 25 patients to determine the incidence of peripheral nerve conduction defects and prospectively evaluate the influence of revascularization in patients with lower extremity ischemia. Ankle pressure indices improved from a mean preoperative value of 0.43 +/- 0.12 to 0.81 +/- 0.26 in patients with aortoiliac disease and 0.40 +/- 0.13 +/- 0.84 +/- 0.19 in the limbs of patients with femoropopliteal disease, P less than 0.001. When compared to controls, there were significant nerve conduction abnormalities detected in the common peroneal and posterior tibial nerves of patients with aortoiliac and femoropopliteal disease preoperatively, P less than 0.02. Postoperatively, there was no improvement in nerve conduction, amplitudes, or velocities in the common peroneal or posterior tibial nerves when compared to preoperative values. However, distal latency in the sural nerve in patients with aortoiliac disease was prolonged indicating deterioration in function. Nerve conduction abnormalities in patients with aortoiliac and femoropopliteal occlusive diseases are often present in patients with lower extremity ischemia and are not significantly improved by revascularization. These observations may indicate nonreversible changes as a result of chronic ischemia.

Adult

Venous complications of sclerotherapy for esophageal varices.

Although endoscopic sclerotherapy is effective in controlling bleeding from esophageal varices, the effects of sclerosing agents on the extrahepatic portal and splenic veins have not previously been investigated. This study of 21 men with portal hypertension and variceal bleeding compares the morphology of the portal and splenic veins in 11 who had received endoscopic sclerotherapy versus 10 patients who did not. The mean number of injections per patient was 11 +/- 5, the mean volume of 1.5 percent sodium tetradecyl injected was 23 +/- 15 ml, and the interval between the last injection and surgery was 15 +/- 6.5 days. Among the 11 patients who had endoscopic sclerotherapy, portal vein thrombosis occurred in 4 (36 percent). Two of these patients died from acute liver failure; the other two had shunt procedures. Histologic changes included intimal thickening and medial fibrosis in seven patients, thrombus in four patients, and destruction of the venous architecture in two patients. Of the 10 patients with portal hypertension who did not have endoscopic sclerotherapy, all had medial fibrosis of the portal vein, with thrombus and intimal thickening present in only 1. These findings suggest that endoscopic sclerotherapy for esophageal varices should be used cautiously in patients who may later require a shunt. Moreover, further studies are necessary to evaluate the long-term effects of injecting sclerosing agents into the portal circulation before widespread use of prophylactic sclerotherapy can be recommended.

Adult

Mesenteric ischemia.

Superior mesenteric artery embolism or thrombosis and nonocclusive ischemia are the most frequent causes of mesenteric ischemia. Symptoms out of proportion to the physical findings, leucocytosis, and metabolic acidosis suggest the diagnosis. A high index of suspicion, aggressive resuscitation and correction of metabolic derangements, early angiography, and operative intervention are necessary if the current high mortality rates are to be reduced.

Humans

The etiology of symptoms in patients with recurrent carotid stenosis.

We performed 33 carotid endarterectomies in 29 patients for recurrent carotid stenosis. The interval between the initial and second operations ranged from six weeks to 11 years with a mean of 56 months. Three types of pathologic lesions were identified: (1) recurrent atherosclerosis (RA), (2) neointimal fibromuscular hyperplasia (NFH), and (3) lesions with elements of both RA and NFH (complex lesions). Histologic examination of early-recurring lesions (less than three years) revealed NFH in 17 patients and one complex lesion. Late-recurring lesions (three years or later) were due to atherosclerosis in eight vessels, NFH in four, and both RA and NFH in three. Focal neurologic symptoms occurred in 25 (76%) of 33 vessels, and an embolic source could be identified in 16 (64%) of 25 patients. Embolic events rather than reduced blood flow due to progressive stenosis are more frequent causes of symptoms in patients with recurrent carotid stenosis than was formerly believed.

Aged

Reliability and sensitivity of frozen-section pancreatic biopsy.

A collaborative Veterans Administration and University of California, Davis Medical Center group of 586 patients with histologically proved pancreatic carcinoma was reviewed. During laparotomy, 159 patients underwent 251 frozen-section pancreatic biopsies with subsequent permanent section examination of the same tissue block. All 112 positive frozen-section diagnoses were corroborated on permanent sectioning. The 47 patients with false-negative biopsy specimens were equally divided between sampling and interpretation error. We conclude that in this group of 159 pancreatic cancer patients, 30% failed to be correctly diagnosed by intraoperative frozen-section biopsy. This failure was due to patient sampling and interpretation error in equal proportion. Interpretation error rates were not influenced by the type or number of biopsies. Patient sampling error is apparently reduced by repeated biopsy, and specimen sampling error occurred less frequently with wedge biopsy.

Biopsy

Trauma to the appendix. A report of two cases.

Only two cases of trauma to the vermiform appendix are recorded in the English literature. This report adds two more cases: one due to a penetrating bullet wound of the abdomen where tangential laceration of the appendix was the only intra-abdominal injury, the other an avulsion of the appendix from the mesoappendix resulting from blunt abdominal trauma. Preoperative diagnosis of this specific lesion could not be made. Both patients were successfully managed by appendectomy.

Abdominal Injuries

Diagnostic laparotomy in the patient with multiple injuries.

Seven hundred consecutive patients with multiple areas of injury requiring surgical repair outside of the abdomen were subjected to laparotomy. Five hundred sixty-one patients had intra-abdominal injury: 139 patients were found to have no intraperitoneal damage. The morbidity in the 139 patients with negative findings at laparotomy was 2%. In patients with multiple areas of trauma, the abdomen is almost always suspect. The proliferation of diagnostic tools to detect intraperitoneal damage have, in some ways, helped physicians decide as to laparotomy. However, when multiple injuries are present, particularly of the central nervous system, classical findings of peritoneal damage are difficult to elicit. A diagnostic laparotomy does not add significantly to the overall morbidity or mortality, and in 25% of the patients in whom intraperitoneal pathology was not strongly suspected, damage requiring surgery was found. We think there is still a place for diagnostic laparotomy in patients with multiple trauma.

Abdominal Injuries

The relationship of intraluminal shunting to technical results after carotid endarterectomy.

This study evaluates the incidence of defects on the intraoperative angiograms of 160 carotid endarterectomies performed in 146 patients, 81 of 160 (50.6%) with a shunt and 79 of 160 operations (49.4%) performed without a shunt. Angiographic defects were identified in 34 of 160 carotid endarterectomies (21%), of which 21 of 34 (65%) resulted in a greater than 20% stenosis of the internal carotid artery (ICA). There were defects in 6 of 81 (7.4%) shunted vessels compared to 16 of 79 (20%) of those not shunted (p less than 0.05). Thirty-one vessels were reexplored 11 of 81 (13.5%) of those shunted and 20 of 79 (20%) of those not shunted (p less than 0.05). There were four strokes (2.5%) (2 in each group) and one death due to myocardial infarction (0.6%) in the postoperative period. Duplex follow-up from 1-60 months (median 22 months) was available in 114 of 160 (71%) endarterectomies. A stenosis of greater than 50% was detected in 7 of 114 (6%) carotid arteries; 5 of the 7 (71%) were shunted and 2 (29%) were nonshunted. Unrepaired defects were present in 3 of 7 (43%) and no defects in the remaining 4 of 7 (57%) arteries. We conclude that the use of a shunt significantly decreases the number of ICA defects detected angiographically and that immediate revision of demonstrable defects can be undertaken with low morbidity and does not predispose the patient to recurrent stenosis.

Aged