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Biomedical subjects

V L Gott

Publications and source records attributed to V L Gott.

At least 55 records · Page 3Linked to original sources
PubMed1987

Comparative analysis of mechanical and bioprosthetic valves after aortic valve replacement.

Comparative long-term performance characteristics of Björk-Shiley mechanical and bioprosthetic valves were analyzed for patients undergoing aortic valve replacement between 1976 and 1981. A total of 419 patients received either a standard Björk-Shiley (n = 266) or bioprosthetic (porcine, n = 126, or pericardial, n = 27) aortic valve. Cumulative patient follow-up was 1,705 patient-years; the average patient follow-up was 4.1 +/- 2.7 years. Survival data were obtained for all but 11 patients (97% complete follow-up) up to 9 years after operation. Survival at 5 years was 81% +/- 4% (+/- standard error) for Björk-Shiley and for bioprosthetic valve recipients. Valve failure in the Björk-Shiley group was predominantly due to valve-related mortality and did not result from structural failure. Patients with bioprosthetic valves experienced valve failure as a result of prosthetic valve endocarditis and intrinsic valve degeneration. Although patients with bioprostheses experienced a lower incidence of valve-related morbidity than Björk-Shiley valve recipients (p less than 0.03), no difference could be demonstrated in the incidence of valve-related mortality or valve failure at 5 years between bioprosthetic and Björk-Shiley valves. Mortality rate from valve failure was higher for Björk-Shiley (86%, 12/14) than bioprosthetic valves (36%, 5/14) (p less than 0.01).

Actuarial Analysis↗
PubMed1987

Free radical scavengers improve functional recovery of stunned myocardium in a model of surgical coronary revascularization.

This study examined whether treatment with the oxygen free radical scavengers, superoxide dismutase and catalase, could improve functional recovery in hearts subjected to regional ischemia and global cardioplegic arrest. Regional left ventricular (LV) function was assessed in open chest pigs with sonomicrometry and micromanometry to calculate an index of regional work from the LV pressure-segment length relationship. After measuring baseline preischemic function, the left anterior descending artery was occluded, creating a region-at-risk in 20% of the LV mass. Cardiopulmonary bypass was begun 15 minutes after initiation of regional ischemia and was followed immediately by cardioplegic arrest for 45 minutes, after which time the coronary artery occluder was removed to simulate coronary revascularization. Starting just before removal of the aortic cross-clamp and continuing for the first 30 minutes of reflow, animals received an aortic root infusion of either superoxide dismutase (3600 U/kg) and catalase (20,000 U/kg) or a control saline solution infusion. In each group, seven animals were successfully weaned from cardiopulmonary bypass without inotropic support. After 2 hour of reperfusion, the recovery of baseline function in the region-at-risk was 44% +/- 7% in the treated animals and 4% +/- 13% in the untreated animals (p less than 0.05). In this experimental model, oxygen free radical scavengers were effective in preserving functional recovery in regionally ischemic myocardium reperfused under conditions simulating surgical revascularization in the setting of acute myocardial ischemia.

Animals↗
PubMed1987

The rapid evolution of a myocardial infarction in an end-artery coronary preparation.

The potential for salvaging infarcting myocardium depends on the time course of the infarction process. To determine the rate of infarct evolution in an end-artery coronary preparation similar to the coronary arterial system of the human heart, each of 84 swine underwent a reversible occlusion of the left anterior descending coronary artery for varying lengths of time, after which flow was reestablished into the occluded region for either 2 or 48 hr. Infarct size was assessed by nitro blue tetrazolium (NBT) staining and confirmed by histologic examination in the 48 hr animals. The region at risk of ischemic injury was determined by injection of monastral blue dye. Infarction progressed rapidly, with a mean of 1.9 +/- 1.5% of the risk region infarcting after 15 min of occlusion, 20.3 +/- 5.7% at 30 min, 43.3 +/- 4.8% at 45 min, 59.9 +/- 2.4% at 60 min, 70.6 +/- 1.7% at 90 min, 84 +/- 2.0% at 180 min, and 88.6 +/- 2.0% after 48 hr. Although there was good correlation in infarct sizing between NBT and histologic techniques at 2 and 48 hr of reperfusion, NBT underestimated infarct size at 15 and 30 min. These data suggest that in the setting of an end-artery coronary anatomy, reperfusion must be carried out within 90 min of coronary occlusion to achieve significant salvage of infarcting myocardium, a period of time much shorter than previously suspected.

Animals↗
PubMed1986

Surgical treatment of aneurysms of the ascending aorta in the Marfan syndrome. Results of composite-graft repair in 50 patients.

The life expectancy of patients with the Marfan syndrome is reduced by complications caused by dilatation of the ascending aorta. Because surgical therapy with a composite graft may alter this natural history, we analyzed the preoperative and long-term postoperative status of 50 consecutive patients who received such a graft. At surgery, the patients had a mean age of 32.2 years and a mean aortic diameter of 7.1 cm (range, 5.3 to 10). Dissection of the ascending aorta was present in 14 patients and was acute in 5. None of the 44 patients who underwent elective repair, and only one of the six patients who had emergency surgery, died in the hospital; thus, the overall hospital mortality was 2 percent. Five of the 49 survivors died during a follow-up period of up to eight years (10.2 percent late mortality). During the most recent four years of evaluation of this series (38 patients), no postoperative deaths due to intrathoracic problems occurred. Actuarial survival was 87 percent at both two and five years. Composite-graft repair of the ascending aorta in patients with the Marfan syndrome can be performed with low operative and long-term mortality. Because of the unfavorable natural history of the Marfan syndrome and the potential for dissection in moderately dilated aortic roots, we recommend prophylactic repair when the aneurysm reaches a diameter of 6 cm.

Adolescent↗
PubMed1986

Retrograde coronary sinus perfusion prevents infarct extension during intraoperative global ischemic arrest.

To determine whether continuous infusion of cardioplegia retrograde through the coronary sinus could improve the salvage of infarcting myocardium, 54 pigs were utilized in a region at risk model. All hearts underwent 30 minutes of reversible coronary artery occlusion, and were divided into six groups. Group 1 served as controls and underwent two hours of coronary reflow without global ischemic arrest. The remaining five groups were subjected to 45 minutes of cardioplegia-induced hypothermic arrest followed by two hours of normothermic reflow. Group 2 had a single infusion of crystalloid cardioplegia, and Group 3 received an oxygenated perfluorocarbon cardioplegic solution initially and again after 20 minutes of ischemia. After initial cardiac arrest with crystalloid cardioplegia, all hearts in Groups 4, 5, and 6 underwent a continuous infusion of a cardioplegic solution retrograde through the coronary sinus. Group 4 received a nonoxygenated crystalloid cardioplegic solution, Group 5 received an oxygenated crystalloid cardioplegic solution, and Group 6 received an oxygenated perfluorocarbon cardioplegic solution. With results expressed as the percent of infarcted myocardium within the region at risk, Group 2 hearts, which received only antegrade cardioplegia, had a mean infarct size of 44.8 +/- 6.3%, a 2.2-fold increase over controls (p less than 0.05). While antegrade delivery of oxygenated perfluorocarbon cardioplegia (Group 3) and coronary sinus perfusion with nonoxygenated crystalloid cardioplegia (Group 4) limited infarct size to 33.6 +/- 4.7% and 35.3 +/- 5.4%, respectively, only oxygenated cardioplegia delivered retrograde through the coronary sinus (Groups 5 and 6) completely prevented infarct extension during global ischemic arrest.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1986

The first open heart corrections of tetralogy of Fallot. A 26-31 year follow-up of 106 patients.

Tetralogy of Fallot became a correctable malformation on August 31, 1954, and from that data through 1960, 106 patients (ages 4 months-45 years) who underwent open repairs at the University of Minnesota and were discharged, have been followed (99% complete) until death or for 26-31 years (mean: 23.7 years, 2424 patient years). The purposes of this study were to determine survival, morbidity, hemodynamics, educational/employment attainments, and relation of these to surgical technics. Operations were done by cross circulation (6 patients) and bubble oxygenator (100 patients). This group had the first uses of patch ventricular septal defect closure, outflow root, infundibuloplasty, atresia correction, ischemic arrests, and pacemakers among other innovations. Twenty-one (of 105 patients) have died during the followup: eight deaths in the first 10 years, 12 between 10 and 20 years, and 1 greater than 20 years. The causes of death were sudden (5), accidental (4), congestive failure (2), reoperation (2), suicide (2), and other (2). Actuarial survival at 30 years was 77%. Late complications were ten reoperations, five arrhythmias, and one endocarditis. Actuarial freedom from reoperations at 30 years was 91%. Cardiac recatheterizations in 62 patients disclosed only 10 with residual shunts. Peak right ventricular systolic pressures were less than 40 mmHg (34 patients), 41-60 mm (2 patients), 61-70 mm (4 patients), greater than 71 mm (4 patients). Thirty-four patients (32%) completed college, ten of these completed graduate school (5 masters degrees, 2 M.D.'s, 2 Ph.D.'s, 1 lawyer). Fifteen others attended college, and nine received technical school diplomas. Forty patients (18 men, 22 women) had progeny, with 82 (93%) live births and six major cardiac defects (7.3%). In summary, complete repair gave excellent late results in this group cared for very early in the open heart era. Survivors led productive lives without restrictions in education and employment. Many of the deaths/complications that occurred are now easily preventable, which augurs extremely well for this generation.

Adolescent↗
PubMed1986

Anatomic and anesthetic considerations in experimental cardiopulmonary surgery in swine.

We have used immature commercial swine (13-25 kg) successfully in a variety of experimental cardiopulmonary surgical procedures in our laboratories since 1981. Multiple drug anesthetic protocols using barbiturates, narcotics, paralytic and antiarrhythmic agents have been employed in over 400 procedures per year. Complications, including fatal cardiac arrhythmias, have been greatly reduced by anesthetic protocols and surgical procedures developed through experience.

Acepromazine↗
PubMed1986

Five year follow-up after valve replacement with the St. Jude Medical valve in infants and children.

Since 1979, 34 infants and children, 3 weeks to 17 years of age, have undergone cardiac valve replacement with a St. Jude Medical (SJM) prosthesis at our institution. Seventeen children underwent mitral valve replacement (MVR), 16 aortic valve replacement (AVR), and one pulmonary valve replacement. Three hospital deaths were associated with MVR and complex congenital heart disease. All surviving patients were functional in class I. A cumulative 89.1 patient-years of follow-up were analyzed to evaluate valve-related mortality and morbidity. Late complications included thromboembolus (one patient), anticoagulant-related hemorrhage (one patient), and perivalvular leak (one patient). One of six late deaths resulted from mitral valve thrombosis. Actuarial 5 year survival for patients who underwent AVR was 100%, but it was 53% for MVR (p = .03). Freedom from significant morbidity and mortality for up to 5 years after operation was 92 +/- 7% for those who underwent AVR and 45 +/- 16% for those who underwent MVR. Patient-related factors appear to account for an increased rate of complications after MVR. Because of difficulties with achieving anticoagulation with warfarin, aspirin therapy should be used for patients less than 5 years of age, while older patients can be managed with warfarin. The SJM valve is a satisfactory cardiac valve substitute for the pediatric age group.

Adolescent↗
PubMed1985

Reperfusion before global ischemic arrest improves the salvage of infarcting myocardium.

To study the effect of hypothermic global ischemic arrest on an evolving myocardial infarction and of perfusion of the ischemic zone or region at risk before global ischemia, 62 farm pigs underwent 15, 30, or 60 minutes of reversible coronary occlusion. Twenty-eight of these animals served as controls: reflow to the region at risk was established by removal of the coronary occluder without the addition of global ischemia. Another 26 animals had similar periods of coronary occlusion and then were placed on cardiopulmonary bypass; they underwent aortic cross-clamping and cardioplegia-induced global hypothermic arrest for 45 minutes. Eight additional pigs had two hours of reflow to the region at risk after removal of the occluder and before global ischemic arrest. When superimposed on regional ischemia, global ischemia resulted in a 6-fold increase in infarct size after 15 minutes of coronary occlusion (p less than 0.05), a 2.2-fold increase after 30 minutes of coronary occlusion (p less than 0.05), and no significant increase after 60 minutes of coronary occlusion. Reperfusion prior to global ischemia completely prevented infarct extension with 0.4% less infarction (not significant) in this group versus the controls without global ischemia. These results clearly demonstrate that infarct extension occurring when global ischemia is superimposed on regional ischemia is greatest early in infarct evolution but that reflow to the region at risk before global ischemic arrest prevents the additional infarction.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1985

Stroke following coronary artery bypass grafting: a ten-year study.

To identify possible risk factors for the occurrence of stroke during coronary artery bypass grafting (CABG), the cases of 3,279 consecutive patients having isolated CABG from 1974 to 1983 were reviewed. During this period, the risk of death fell from 3.9% to 2.6%. The stroke rate, however, fell initially but then rose from 0.57% in 1979 to 2.4% in 1983. Adjustment of these data for age clearly demonstrated that the risk of stroke has increased largely because of an increase in the mean age of patients undergoing CABG procedures. A case-control study involving all 56 stroke victims and 112 control patients was used to identify those risk factors significantly associated with the development of stroke in univariate analysis: increased age (63 versus 57 years in stroke patients and controls, respectively; p less than 0.0001); preexisting cerebrovascular disease (20% versus 8%; p less than 0.03); severe atherosclerosis of the ascending aorta (14% versus 3%; p less than 0.005); protracted cardiopulmonary bypass time (122 minutes versus 105 minutes; p less than 0.005); and severe perioperative hypotension (23% versus 4%; p less than 0.0001). Other variables not found to correlate with postoperative stroke included previous myocardial infarction, hypertension, diabetes mellitus, lower extremity vascular disease, preoperative left ventricular function, and intraoperative perfusion techniques. Elderly patients who have preexisting cerebrovascular disease or severe atherosclerosis of the ascending aorta or who require extensive revascularization procedures have a significantly increased risk of postoperative stroke.

Age Factors↗
PubMed1985

Late false aneurysm following replacement of ascending aorta: the problem of the teflon graft in combination with a silk suture anastomosis.

Two patients underwent resection and replacement of the ascending aorta using a low-porosity Teflon graft anastomosed with silk suture. In both patients false aneurysms developed that required operation 13 and 23 years postoperatively. The clinical courses of these patients, along with data from the literature, suggest that the combination of a low-porosity Teflon graft and a silk suture anastomosis presents a major potential hazard for the development of anastomotic false aneurysm.

Adult↗
PubMed1985

Coronary artery bypass grafting in women. A ten-year perspective.

Between January 1974 and December 1983, 3279 patients have undergone isolated coronary artery bypass (CAB) grafting at the Johns Hopkins Hospital. There were 639 women in this group. Women represented 18 to 22% of the patients having isolated CAB grafting throughout the 10-year period, except in 1976 when only 13% of the CAB patients were women. Mean age-at-operation for women has increased from 53.9 to 61.1 years since 1974, and was higher than the mean operative age of men during each of the 10 years. Although the oldest woman undergoing CAB grafting in 1974 was 64 years old, the eldest in 1983 was 84 years old. Except for an older mean age-at-operation for women and a higher incidence of unstable angina prior to surgery, the only other significant difference in the clinical status of female versus male CAB patients, detected by a case control analysis, was the smaller body surface area of women compared to men. Although operative mortality was significantly greater for women during most of this review period, mortality was similar during 1983 (2.6% for men versus 2.4% for women), in spite of a significantly higher incidence of unstable angina in the female group (54% for women versus 35% for men). The improved survival noted following coronary bypass grafting in women, which occurred in spite of the advancing age of the female group, supports an aggressive approach to surgical intervention in women with severe coronary artery disease.

Age Factors↗
PubMed1984

Identification of patients at high risk for complications of intraaortic balloon counterpulsation: a multivariate risk factor analysis.

Risk factors for vascular complications of intraaortic balloon (IAB) counterpulsation were evaluated in 206 consecutive patients. The approach was percutaneous in 105 patients and surgical cutdown in 101. Vascular complications occurred in 42 patients, and of these 21 required surgery. Multivariate analysis demonstrated the following major risk factors for vascular complications: preexisting peripheral vascular disease (PVD) defined as a history of claudication, femoral bruit or absent pedal pulse (p less than 0.01); and the use of the percutaneous approach (p = 0.02). Evidence of PVD was particularly predictive of major vascular complications requiring surgery (p less than 0.01). In patients with evidence of previous PVD, the risk for a major vascular complication was 31% with the percutaneous, and 16% with the surgical cutdown approach. Without PVD, the risk for a major vascular complication was 4 times higher in women (15%) than in men (3.5%), but in the presence of PVD gender had no significant effect (p = 0.03). Age, duration of IAB counterpulsation and indication for insertion were not significant risk factors. It is concluded that (1) without previous PVD, women are at greater risk than men for major vascular complications (due to smaller arterial size); and (2) evidence of previous PVD identifies patients at high risk for major vascular complications with IAB counterpulsation, particularly by way of the percutaneous approach.

Assisted Circulation↗
PubMed1984

Identification and control of noncoronary collateral blood flow.

To identify the source of noncoronary collateral myocardial blood flow and to establish methods to control it during induced ischemia, 29 dogs were placed on cardiopulmonary bypass. The right and left ventricles were vented, vent flows were measured volumetrically, and intracavitary left ventricular (LV) pressures were monitored. After induction of ischemia by aortic cross-clamping and infusion of cardioplegic solution, six different microspheres 7 to 10 microns in diameter were injected into the aorta at six different times to measure myocardial blood flow during the following interventions:vent drainage of the right or left ventricle or both, proximal ligation of both coronary arteries, severance of the proximal pulmonary artery or the ascending aorta or both, and ligation of the bronchial arteries. Without effective LV venting, LV intracavitary pressure rose to 7.0 +/- 0.1 mm Hg (mean +/- standard error of the mean) and myocardial blood flow in the anterior left ventricle was 2.3 +/- 1.3 ml/100 gm/min. When the LV vent was opened, vent flow was 35.9 +/- 3.5 ml/min and myocardial blood flow fell to 0.3 +/- 0.2 ml/100 gm/min. Right ventricular (RV) vent flow was absent except when the LV vent was occluded, and this RV vent flow was abolished by ligating the coronary arteries. With bronchial artery ligation, LV vent flow ceased and myocardial blood flow was virtually absent. These studies demonstrate that myocardial blood flow does occur during induced ischemia, but that the source of this blood flow is primarily through systemic-pulmonary channels. True noncoronary collateral myocardial blood flow was virtually nonexistent.

Animals↗
PubMed1984

Operative intervention for postinfarction angina.

Thirty-four patients (26 men and 8 women) underwent myocardial revascularization following myocardial infarction (MI) at the Johns Hopkins Hospital during 1980 through 1982. Average age was 59 years. Of the 33 patients with unstable angina, 61% had ischemia in the infarct zone and 39% had "ischemia at a distance." Mean time from MI to operation was 16 days. The MIs were equally divided between a transmural and a subendocardial location. Eleven patients had a history of congestive heart failure. Intraaortic balloon pumping was used preoperatively for anginal stabilization in 14 patients. Mean ejection fraction for the group was 52%. There were 3 operative deaths, all 3 due to myocardial failure. Late follow-up (mean, 13.7 months; range, 6 to 35 months) is complete for 28 patients. There was 1 late death, secondary to cardiac failure. There were no late MIs. Angina had recurred in 5 patients, but only 2 were taking antianginal medication. At the time of follow-up, 52% of patients were in New York Heart Association Functional Class I. This experience suggests that operative intervention for postinfarction angina can be accomplished with an acceptable mortality and thereby increase survival, reduce the later occurrence of MI, and relieve angina in this high-risk group.

Aged↗
PubMed1984

Mediastinal infection after cardiac surgery.

Mediastinitis is an uncommon complication after cardiac surgery; however, its associated morbidity and mortality demand early recognition and emergency therapy. This review is intended to emphasize certain features of the incidence, pathogenesis, and bacteriology of this complication in patients undergoing cardiopulmonary bypass through a median sternotomy. The diagnosis and treatment of mediastinitis after cardiac surgical procedures, as well as methods of prevention, are also reviewed.

Anti-Bacterial Agents↗
PubMed1983

The Budd-Chiari syndrome. Treatment by mesenteric-systemic venous shunts.

Twelve patients with the Budd-Chiari syndrome have been managed surgically. Ten of the patients were female, two were male, with a mean age of 40 years. Three of the patients had polycythemia vera, two had pre-existing cirrhosis, one had ingested estrogens, one had an occult tumor, and in four there were no associated factors. Ten patients presented with ascites and two with bleeding esophageal varices. The diagnosis was confirmed in all 12 patients by liver biopsy and hepatic vein catheterization. Inferior vena cavography revealed the abdominal vena cava to be thrombosed in six patients. The superior mesenteric vein was used to decompress the congested liver in all 12 patients. In five patients, a mesocaval shunt (MCS) was performed and in seven patients, a mesoatrial shunt (MAS) was carried out. There were four hospital deaths (two MCS, two MAS). One late death (MAS) occurred from liver failure following shunt thrombosis. Two additional patients (one MCS, one MAS) re-developed ascites immediately following surgery and angiography revealed a thrombosed shunt. Ascites has been controlled with a LeVeen shunt in these two patients, but liver biopsies showed progression to cirrhosis. The remaining five patients (three MAS, two MCS) did well, and angiography revealed patent shunts. Two of these patients, however, re-developed ascites at 4 and 10 months following MAS and required a second MAS. Follow-up ranges from 6 to 68 months. In three of the patients (two MCS, one MAS) with patent shunts, liver biopsy shows a remarkable return toward normal liver architecture and histology.

Adolescent↗