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Biomedical subjects

J N Cunningham

Publications and source records attributed to J N Cunningham.

At least 163 records · Page 9Linked to original sources
PubMedDate not supplied

Internal mammary artery bypass: thirteen years of experience. Influence of angina and survival in 5125 patients.

Internal mammary artery (IMA) bypass to the anterior descending coronary artery (ADA) was performed in 5125 patients from January 1978 to December 1990. The average age of patients was 68 years; males accounted for 68% (3485 patients) and 82% (4203) were NYHA Class III. Left ventricular function was impaired (ejection fraction < 40%) in 68% (3485 patients). The average number of additional saphenous vein graft (SVG) per patient was 2.2. Operative mortality was 1.8%. Mediastinitis occurred in 51 patients (1.0%). Reoperation for bleeding was necessary in 56 patients (1.1%). Perioperative myocardial infarction was seen in 102 patients (2.0%) and neurological complications occurred in 51 patients (1%). Repeat coronary angiography was performed in 1414 patients (28%) and demonstrated a patency rate of 96% in IMA grafts and 75% in SVG grafts (p < 0.001). Survival at 13 years was 80% from all causes and 90% when non-cardiac deaths were excluded. Recurrence of angina occurred in 768 patients (15%) and reoperation or PTCA was performed in 61 (1.2%). During the same time period, 2345 patients underwent coronary artery bypass utilizing solely SVG. Survival at 13 years was 68% from all causes and 78% when non-cardiac deaths were excluded (p < 0.001). Recurrent angina was present in 727 patients (31%) (< 0.001). This data suggests that long-term probability of cumulative survival and occlusion free survival were significantly greater and the probability of recurrent angina and reoperative CABG and death from cardiac causes were significantly less in the IMA patients and should be the conduit of choice in coronary bypass surgery.

Adult↗
PubMedDate not supplied

Laser welding and irradiation in alcohol preserved homografts.

This experiment examined the effect of laser welding and irradiation on the patency rate of microvascular anastomoses done with alcohol preserved homografts. The carotid arteries from Sprague-Dawley rats were freshly harvested and preserved in 70% ethyl alcohol for at least 3 weeks. The homografts were interposed into the carotid arteries with one of the following techniques: Group I, grafts were anastomosed with three stay sutures and laser welding (carbon dioxide laser, 90 mW); Group II, anastomoses were completed with eight to nine interrupted sutures (10-0 nylon); or Group III, the same technique used in Group II, but followed by laser irradiation (90 mW for 1 min) of the grafts. These results showed that patency at 2 weeks was 73% in Group I, 71% in Group II, and 82% in Group III, respectively. The patency at 12 weeks was 67% in Group I and unchanged in Groups II and III. In conclusion, laser irradiation and laser welding did not increase the patency rate of microvascular anastomoses done with alcohol preserved homografts. Thrombotic occlusion in microvascular homografts usually occurs before the second week postoperatively.

Anastomosis, Surgical↗
PubMedDate not supplied

Preservation of spinal cord function and prevention of paralysis during aortic occlusion via veno-arterial bypass.

Paraplegia secondary to spinal cord ischemia is a too frequent devastating complication of thoracic aneurysm surgery. We examined the ability of veno-arterial bypass (VAB) to ensure adequate spinal cord blood flow during aortic cross-clamping by monitoring spinal cord function via somatosensory evoked potentials (SEP's) and postoperative motor function. Dogs were placed on VAB using a heparin-bonded roller pump circuit without systemic heparinization. SEP latency and amplitude were monitored continuously. The respirator FIO2 was set at 100% while the aorta was cross-clamped for one hour with the bypass adjusted to keep distal arterial pressure at greater than 60 mmHg. After one hour the aorta was unclamped, bypass discontinued, and the animals recovered. SEP's were always present during VAB as long as the distal pressure was kept at greater than 60 mmHg. There were several transient hypotensive episodes (less than 5 min) which were accompanied by reversible loss of SEP's. None of the animals displayed any gait abnormalities post-op. These findings using this simple bypass technique suggest the following conclusions: (1) SEP's degenerate (increased latency and decreased amplitude) in response to hypoxia; (2) spinal cord function can be maintained for up to one hour during hypoxic conditions; (3) SEP's can be used to monitor sensory spinal cord function under these conditions; and (4) heparinless VAB can provide spinal cord protection while also allowing monitoring of SEP's to ensure adequate spinal cord perfusion.

Animals↗
PubMedDate not supplied

Repair of ventricular rupture following mitral valve replacement.

Left ventricular rupture is reported to occur in 0.5-2% of patients following mitral valve replacement and results in a high mortality rate. Three types of left ventricular rupture have been identified, each attributed to a different mechanism. Failure of repair has been due to repeated tearing of the ventricular muscle and resulting hemorrhage. We describe the repair of left ventricular rupture following mitral valve replacement with buttressed dacron patch. The repair is designed to eliminate the tension placed on the suture line. In addition, specific recommendations are made to avoid left ventricular rupture during mitral valve replacement.

Female↗
PubMedDate not supplied

Early coronary artery bypass grafting for complicated acute myocardial infarction.

The occurrence of unstable angina or cardiogenic shock after an acute myocardial infarction characterizes a subgroup of patients with increased morbidity and mortality. To assess the efficacy of surgical revascularization in this cohort, 96 patients who underwent coronary artery bypass grafting within 6 weeks of an acute myocardial infarction were compared to 485 patients who underwent myocardial revascularization without recent infarction. Fourteen (15%) of the patients with acute infarction were in cardiogenic shock and 82 (85%) patients had unstable angina at the time of surgery. Preoperatively, the patients with acute infarction compared to the patients without acute infarction were older (+3.5 years), had an increased incidence of congestive heart failure (21% vs 13%), and had a lower mean ejection fraction (4% vs 65%). Preoperative intraaortic balloon support was used in 9 patients (65%) with cardiogenic shock, and in 16 patients (19%) with unstable angina. Mean interval to surgery from time of infarction was 14.9 days. Overall operative mortality was 7.3% (7 patients) for the acute infarction group 28% for patients with cardiogenic shock and 3.7% for patients with unstable angina compared to 3.7% for the group of patients without recent infarction. Earlier surgical intervention did not result in a significant increase in operative mortality. Discriminant analysis of the recent infarction cohort demonstrated that preoperative ejection fraction less than 45% and age greater than 70 were the most significant predictors of early mortality. Of the 89 patients surviving surgery, actuarial survival was 97% at 3 years with no late infarctions. At follow-up 95% of survivors were NYHA Class I or II.(ABSTRACT TRUNCATED AT 250 WORDS)

Angina, Unstable↗
PubMedDate not supplied

Role of coronary angiography and coronary artery bypass surgery prior to abdominal aortic aneurysmectomy.

It is well recognized that patients with abdominal aortic aneurysms have a high incidence of coronary artery disease, and that the major cause of death in patients undergoing aneurysmectomy has been acute myocardial infarction. In order to assess the incidence of significant coronary artery disease, cardiac catheterization was performed on 42 consecutive patients with abdominal aortic aneurysms. Thirty-six patients (85.7%) had significant anatomic coronary artery disease. Interestingly, all 8 patients with ejection fractions of less than 50% had triple vessel disease or left main disease, and 12 of 34 patients with ejection fractions greater than or equal to 50% had triple vessel disease or left main disease. Of the 30 patients who were NYHA Class I or Class II, 14 (46.7%) had triple vessel disease or left main disease. All 20 patients with triple vessel disease or left main disease underwent myocardial revascularization 7 to 10 days prior to abdominal aneurysmectomy. No patients had a perioperative myocardial infarction either following coronary artery bypass surgery or abdominal aortic aneurysm resection, and there were no operative mortalities. Although this was not a randomized study, it would seem from these results that in selected patients, myocardial revascularization prior to abdominal aneurysmectomy can decrease the incidence of acute myocardial infarction and also decrease operative mortality. It is presently recommended that all symptomatic patients, patients with ejection fractions of less than 50%, and asymptomatic patients with ejection fractions of greater than or equal to 50% with positive exercise radionuclide angiography undergo cardiac catheterization prior to aneurysmectomy, and those patients with left main disease or severe coronary artery disease undergo myocardial revascularization prior to aneurysm resection.

Aged↗
PubMedDate not supplied

Preservation of myocardial ATP during cardioplegia: comparison of techniques.

Preservation of myocardial ATP enhances the heart's ability to resume normal function following aortic crossclamping (AXC). Preservation of this high energy substrate during 4 cardioplegia delivery techniques was evaluated and compared with changes occurring during 4 hours of continuous coronary perfusion. Dogs (31) were placed on cardiopulmonary bypass and transmural left ventricular biopsies obtained for control ATP measurements. Animals were then divided into five groups: Group I (n = 6): 4 hrs. of continuous coronary perfusion (CCP); Group II (n = 6): 3 hrs. continuous AXC, multidose blood cardioplegia (MBC); Group III (n = 6): 3 hrs. continuous AXC, multidose crystalloid cardioplegia (MCC); Group IV (n = 6): 2 hrs. intermittent AXC, single dose BC (SBC); Group V (n = 7): 2 hrs. continuous AXC, continuous perfusion BC (CBC). In each group, where applicable, myocardial biopsies were taken at 30 minute intervals during AXC, before and after cardioplegia injection, and 30 minutes following final unclamping and rewarming. Hearts in Group II (MBC) and V (CBC) showed greatest preservation of ATP stores (increases 1.1 +/- 1.2%, increases 1.8 +/- 0.9% respectively; p greater than .05) ATP levels rose as high as 23 +/- 2% (p less than .005) above control immediately following cardioplegia injection in Group II (MBC). Group IV showed poorest preservation of ATP (decreases 26 +/- 5%, p less than .01) with levels falling as much as 37 +/- 10% (p less than .01) during the period of AXC. Hearts in Group I (CCP) demonstrated a 15.6 +/- 7.5% decrease in ATP from control (p less than .05). Group III (MCC) also showed a steady decline in ATP declining 18 +/- 3% (p less than .005) from control. These data indicate that multidose blood and continuous-blood cardioplegia techniques will maintain normal myocardial ATP stores throughout the period of AXC. These groups actually show a slight rise in ATP as compared to 4 hrs. of continuous coronary perfusion.(ABSTRACT TRUNCATED AT 250 WORDS)

Adenosine Triphosphate↗