Nifedipine: a myocardial protective agent.

The effectiveness of the calcium antagonist nifedipine in preserving postischemic myocardial function and structural integrity was experimentally demonstrated in isolated rabbit hearts, in conscious dogs subjected to myocardial infarction, in open chest anesthetized dogs with normothermic regional ischemia induced for 1 to 2 hours and in dogs undergoing hypothermic global ischemia for 2 hours followed by 2 hours of reperfusion. Nifedipine had a beneficial effect on postischemic myocardial stiffness and mitochondrial calcium accumulation, which were correlated. Administration of nifedipine at the onset of myocardial infarction increased blood flow to ischemic zones of myocardial infarction and resulted in less loss of creatine kinase. It reduced by two- to three-fold the volume of the ischemia-reperfusion injury induced by left anterior descending coronary arterial occlusion and release and preserved indexes of hemodynamic function. Nifedipine was found effective in protecting myocardial performance and structure after 2 hours of global ischemia during hypothermic cardiopulmonary bypass. It is suggested that this agent may be useful as an adjunct to cold cardioplegia in man for enhanced myocardial protection during cardiac surgery.

Surgical resection of carotid body tumors: long-term survival, recurrence, and metastasis.

We retrospectively reviewed a 20-year experience with 59 carotid body tumors in 55 patients examined at our institution in order to determine the long-term results of surgical resection, including the rates of distant metastasis, local recurrence, and long-term survival. Complete surgical excision was possible in 52 of the 55 patients (95%). Perioperative mortality was only 2% (1 of 59 procedures), and no operative deaths occurred during the last 10 years of the study. Survival of patients after resection of a carotid body tumor was equivalent to that for sex- and age-matched control subjects. Only one patient (2%) had development of metastatic disease during long-term follow-up. Three patients (6%) had recurrence of the carotid body tumor after complete excision. All recurrent tumors were observed in patients with multiple paragangliomas or a family history of cervical paragangliomas. Therefore, we advocate early surgical resection of all carotid body tumors in low-risk patients. Such early resection maximizes the possibility of cure and minimizes the risks of neurovascular complications associated with large and neglected tumors.

Cardiac and renal responses to cross-clamping of the descending thoracic aorta.

The present study was performed to document the relative efficacy of commonly applied techniques used adjunctively during 1 hour of descending thoracic aortic cross-clamping. Renal and cardiac responses were determined by standard laboratory methods. There were four experimental groups: (1) heparin-bonded shunt; (2) partial femoral-femoral bypass; (3) sodium nitroprusside; (4) control. Each of the experimental groups showed abnormal hemodynamic responses during cross-clamping. Elevations in left ventricular end-diastolic pressure (LVEDP) and systolic blood pressure were common events during clamping, and cardiac output often decreased. Nevertheless, left ventricular performance curves after cross-clamping showed similar increases in left ventricular stroke work (LVSW) with increasing preload. In addition, left ventricular biopsy specimens showed preservation of myocardial high-energy phosphate stores and essentially normal ultrastructural integrity. Radioactive microspheres generally showed increased myocardial blood flow during and after cross-clamping, but no evidence of preferential subendocardial ischemia. Examination of renal function showed a marked decrease in urine output, glomerular filtration rate, and renal plasma flow during cross-clamping. Following the release of the cross-clamp, renal function returned to 50% to 85% of baseline status. Since we could find no major advantage of any of the techniques employed under the present experimental conditions, we suggest that all of the techniques should be part of the surgical armamentarium and the particular preoperative and/or intraoperative findings in a specific case should determine which technique is most appropriate for a given patient.

Contained rupture of the suprarenal aorta.

A contained rupture of the aorta is a rare event; however, this has been recognized with increased frequency in the abdominal aorta. There have previously been two reports of the containment of rupture of the suprarenal aorta. We report two additional cases of contained rupture of the suprarenal aorta, one caused by a penetrating atherosclerotic ulcer, the other from a ruptured aneurysm. Surgical treatment was successful in both patients.

Trends in neurovascular complications of surgical management for carotid body and cervical paragangliomas: a fifty-year experience with 153 tumors.

Almost 75% of carotid body and cervical paragangliomas are adherent to or surround adjacent arteries and cranial nerves. Their resection can result in neurovascular injury, stroke, and excessive blood loss. To assess trends in neurovascular complications, we reviewed 153 carotid body and cervical paragangliomas that were surgically managed between 1935 and 1985. Results of the past 10 years were compared with two previous time periods: period I (1935 to 1965), when carotid artery reconstruction was uncommon at our institution, and period II (1966 to 1975), when methods of intraoperative electroencephalographic monitoring and carotid patch angioplasty were being developed. During the past 10 years (period III), surgical approach to these tumors has included intraoperative monitoring of cerebral blood flow, selective use of shunts, vein patch or graft reconstructions after extensive tumor resections, and mobilization of the parotid gland to facilitate adequate exposure of high tumors. Although tumor resection was attempted in 80% of patients in period I, surgical resection was complete in 98% during periods II and III. Three trends were observed: (1) The perioperative stroke rate has decreased dramatically from 23% in period I to 2.7% in period III (p = 0.007); (2) the perioperative mortality rate has been reduced from 6% in period I to no deaths in the past 10 years, but (3) the rate of postoperative cranial nerve dysfunction remains unchanged over 50 years (period I, 46%; period III, 40%). The median tumor size among patients with postoperative complications was significantly larger than those without complications (median size: 17 vs. 7 cm3, p = 0.004).(ABSTRACT TRUNCATED AT 250 WORDS)

Concomitant abdominal aortic aneurysm and colorectal carcinoma: priority of resection.

Seventeen patients (15 men and two women) underwent operation for concomitant abdominal aortic aneurysm (AAA) and colorectal carcinoma (Ca) during a recent 12-year period. Ages ranged from 59 to 89 years (median 75.2 years). Diameter of the AAA ranged from 3.5 to 9.5 cm (median 5.5 cm). The Ca was staged by the Astler-Coller modification of Dukes' classification as B1 in three patients, B2 in eight, C2 in three, D in two, and unclassified in one. Personal preference, presence of symptoms, and extent of malignant involvement determined preference of resection. The Ca was eventually resected in 16 patients and the AAA in nine. Thirteen patients underwent resection of the Ca first, two the AAA first, and two concomitantly. Eight patients (47%) underwent resection of both the AAA and Ca, eight underwent resection of the Ca only, and one underwent resection of the AAA only. There were three deaths in 24 operations. Follow-up ranged from 5 weeks to 8 years (median 1 1/2 years). Only five patients (29.4%) were long-term survivors without evidence of recurrent Ca and all occurred in the eight patients (62.5%) who had undergone resection of both the Ca and AAA. Three late deaths occurred as a result of complications from the unresected AAA in the eight patients who had undergone resection of the Ca only (37.5%). We conclude that if the Ca is not symptomatic and localized the AAA should be resected first. However, both lesions need to be resected eventually for long-term survival.