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Biomedical subjects

J M Craver

Publications and source records attributed to J M Craver.

At least 91 records · Page 5Linked to original sources
PubMed1981

Coronary bypass for relief of persistent pain following acute myocardial infarction.

Between January, 1976, and April, 1980, 116 patients had urgent myocardial revascularization for clinical instability within 30 days of acute myocardial infarction (MI). Group 1 (8 patients) had coronary bypass grafting within 24 hours of acute MI; Group 2 (20 patients) had coronary bypass grafting 2 to 7 days after acute MI; and Group 3 (88 patients) had coronary bypass grafting 8 to 30 days after infarction. Indications for operation were persistent or recurrent pain (81%), pain plus ventricular arrhythmias (12%), and pain plus compelling anatomy. The incidence of single-vessel, triple-vessel, and left main coronary artery disease was 28%, 31%, and 12%, respectively. There were no hospital deaths in the series. The incidence of inotropic requirements, postoperative intraaortic balloon pumping, ventricular arrhythmias, and perioperative infarction was higher in patients operated on within 7 days of acute MI than for patients having coronary bypass grafting after this time. There have been 5 late deaths during a mean follow-up of 14 months. Actuarial survival was 97% at 18 months. Seventy-one percent of patients are presently pain free. Graft patency was 84% in 17 patients recatheterized after coronary bypass grafting and in 14 patients, grafts placed into the area of infarction were patent. This study suggests that the frequency of perioperative complications will be increased in patients operated on within one week of MI, but after this period, coronary bypass grafting can be accomplished with the same morbidity as the of elective operation.

Angina Pectoris↗
PubMed1981

Hemodynamic changes during fentanyl--oxygen anesthesia for aortocoronary bypass operation.

Fentanyl in doses of 50-60 microgram/kg has been reported to produce anesthesia with remarkable hemodynamic stability in patients with coronary artery disease (CAD). Because the authors had observed hypertension and tachycardia in response to noxious stimulation during aortocoronary bypass (ACB) operations in patients so anesthetized, they studied the hemodynamic changes and anesthetic conditions produced by fentanyl/O2/relaxant anesthesia in patients undergoing elective ACB. Twelve patients with left ventricular (LV) ejection fractions greater than 0.4 were maintained on propranolol until 10 hours before operation and were premedicated with fentanyl, diazepam, and scopolamine. Cannulae were inserted before the study commenced for measurement of intravascular pressures, arterial blood gases, and thermodilution cardiac output. The patients breathed 100 per cent oxygen throughout the study. Controlled ventilation aided by succinylcholine to reduce truncal rigidity maintained PaCO2 at 30-45 torr. Measurements were made after each of the following: breathing oxygen (control), 10 microgram/kg fentanyl, 50 microgram/kg fentanyl, and 0.1 mg/kg pancuronium, tracheal intubation, skin incision, and sternotomy. Fentanyl alone produced no significant hemodynamic changes. Fentanyl and pancuronium in combination produced increased heart rate and reduced stroke volume. Significant and progressively greater increases in mean arterial pressure and systemic vascular resistance followed intubation, skin incision, and sternotomy. Chest rigidity occurred in every patient at a lower fentanyl dose than did unresponsiveness. While fentanyl, 62.4 +/- 2.9 microgram/kg (SE), produced minor hemodynamic changes, it failed to block hemodynamic responses to noxious stimulation. Such changes resulted in increased cardiac work, and could have affected myocardial oxygen balance unfavorably. In eight of the 12 patients, following the last set of measurements, supplementary anesthetic agents were required to maintain hemodynamic stability during the surgical procedure. The authors suggest that this fentanyl/O2/relaxant technique should be modified for patients with severe CAD and reasonably good LV function.

Blood Pressure↗
PubMed1981

Influence of left ventricular aneurysm on survival following the coronary bypass operation.

Patients having coronary bypass and aneurysm resection (N = 40) or aneurysm plication (N = 32) were compared with patients having coronary bypass without aneurysm (N = 2782). Unlike other series, the primary indication for surgery in the aneurysm patients was angina pectoris, with heart failure playing a secondary role. Multivessel disease was present in 83% of the patients with aneurysm. Total occlusion of the anterior descending coronary artery was more prevalent in the group of patients who had aneurysmectomy (75%) than in rhe group of patients who had plication (38%), and more grafts/patient could be performed in the plication group (2.6 vs 2.0). Location of the aneurysm was most often anteroapical (N = 55) and infrequently inferior (N = 6). Septal wall motion was akinetic or aneurysmal in 47% of the aneurysmectomy group, and 10% of the plication group. Postoperative requirements for inotropes or intra-aortic balloon assist was much higher in the aneurysm group (aneurysmectomy or plication) than in patients without aneurysm having bypass. Hospital mortality for aneurysm patients was 2.7% versus 1.4% in patients without aneurysms having coronary bypass. The actuarial survival rate at 42 months for all aneurysm patients was 90%. Improvement in anginal symptoms after plication and coronary bypass (96%) was more frequent than with aneurysmectomy and coronary bypass (76%) and this was attributed to larger viable muscle mass and greater revascularization. Although two-thirds of patients having surgery for aneurysms had improvement in heart failure symptoms after operation, 30% of those having aneurysmectomies and 35% of those having plications said they were unimproved after surgery. However, this could be explained by the finding that a significant number (35% of the aneurysmectomy and 45% of the plication group) were in heart failure Class I prior to operation. Hospital mortality has been progressively reduced and late survival increased by the surgical treatment of left ventricular aneurysm, primarily through early operation at a time when coronary bypass can be used as an adjunct to aneurysm resection or plication.

Aged↗
PubMed1981

Reduced efficacy of coronary bypass surgery in women.

To estimate long-term efficacy of coronary bypass surgery, we examined our experience with 3155 patients observed over a 78-month period. Preoperative clinical profile, operative risk, and long-term symptomatic status and survival were compared in 2663 men and 492 women. To minimize influence of unequal baseline characteristics, surgical results were also compared in 412 pairs of men and women matched by computer for age, preoperative angina classification and number of diseased vessels. Operative mortality was not significantly different in matched patients. Women had smaller distal coronary arteries, more diabetes and hypertension, a higher rate of incomplete revascularization, and reduced graft patency compared with men. Cumulative survival for men and women was 92% at 42 months. At late follow-up, significantly more men were asymptomatic (70% vs 52%, p less than 0.001) and men achieved higher activity levels. We conclude that men have more symptomatic relief after coronary bypass surgery than women. A better-quality revascularization in men may be part of the reason for this outcome.

Coronary Artery Bypass↗
PubMed1980

Clinical, anatomic and functional descriptors influencing morbidity, survival and adequacy of revascularization following coronary bypass.

Clinical data on 3,479 consecutive patients having coronary bypass surgery were retrospectively analyzed. Perioperative complications, incomplete revascularization, and reduced long-term survival could frequently be correlated with manifestations of myocardial damage. Patients with triple vessel and left main coronary disease had a greater frequency of inotropic requirements than did patients with single or double vessel disease (7.9% and 8.6% vs. 3.8% and 4.2%). Inotropic requirements in the perioperative period were significantly increased for patients with preoperative left ventricular dysfunction; a history of heart failure or multiple infarctions did not significantly increase the incidence of inotropic requirements. Presence of previous myocardial infarction, heart failure, or left ventricular contraction abnormalities significantly decreased the ability to achieve complete revascularization with bypass grafting. Hospital mortality since 1976 has been 0.8% (25/3,040). Hospital mortality was significantly increased by history of myocardial infarction, hypertension, heart failure, extent of anatomic disease, presence of preoperative ST-T wave changes, and severe abnormalities of left ventricular function. Hospital mortality in patients with ejection fraction </=0.35 was 3.4% vs. 1.3% for those >0.35. Anginal pattern, history of hypertension, previous myocardial infarction, preoperative heart failure all significantly affected long-term survival. Occurrence of perioperative myocardial infarction did not adversely influence long-term survival. Patients with normal left ventricular function had excellent 42 month survival regardless of vessel disease (95%, 96%, and 94% for single, double, and triple vessel disease, respectively). Survival was significantly less for such patients with abnormal left ventricular function. Inability to achieve complete revascularization did not adversely affect hospital mortality, but did significantly reduce late survival. The important effect which complete revascularization had on long-term survival appeared to increase with increasing severity of coronary disease. Although bypass grafting improves survival in patients with multivessel disease and left ventricular dysfunction, the benefits appear to be significantly reduced once manifestations of left ventricular damage have occurred.

Adult↗
PubMed1980

The spectrum of left main coronary artery disease: variables affecting patient selection, management, and death.

A total of 178 patients having a diagnosis of left main coronary artery stenosis were divided into three groups as follows: surgical, Group I (n = 135 patients); operable medically treated, Group II (n = 21 patients); and inoperable, Group III (n = 22 patients). Groups 1 and 2 were comparable with regard to clinical profile, extent of anatomic coronary disease, and left ventricular function. Inoperable patients had a much higher incidence of prior myocardial infarction (especially anterior), more severe distal coronary disease, and markedly depressed left ventricular function. The hospital mortality rate for surgical patients was 4% (6/135). The late mortality rate, (median follow-up = 23.4 months) was 7% (9/135). For operable patients, the late mortality rate was 43% (9/21) at 28 months. In the inoperable group, the late death rate at 20 months was 59% (13/22). Actuarial survival at 24 months for the three groups was: 88%, 66%, and 42%, respectively. Of the nine patients who died in the operable group, two had less than 75% obstruction of the left main coronary artery and two had normal left ventricular wall motion. Although patients with higher grades of left main coronary artery stenosis and reduced left ventricular function are at greater risk, patients with less obstruction and good left ventricular function are also at risk and should have myocardial revascularization with some sense of urgency. The population of left main coronary artery stenosis is a heterogeneous one, and comparison of surgical versus medical therapy should exclude inoperable patients. The operative mortality rate has been greatly reduced in recent years (2% in the last 100 cases); this is attributed to careful monitoring in the critical prebypass period, aggressive pharmacologic treatment of increased preload, tachycardia, and hypertension, and improved aurgical technique, with emphasis on careful myocardial preservation. Adherence to these principles makes frequent use of the intra-aortic balloon either before or after revascularization unnecessary.

Cardiac Catheterization↗
PubMed1979

What role should the intra-aortic balloon have in cardiac surgery.

Intra-aortic balloon pumping (IABP) to assist the failing circulation has become widely applied and accepted since its introduction in 1968. The elective, preoperative use of IABP for patients undergoing cardiac surgery has now become the controversy. The purposes of this report are to examine our experience with IABP and to determine its appropriate role in high-risk patients. IABP was utilized in 75 of 2333 (3.2%) adult cardiac surgical patients at Emory University Hospital from January 1976 through June 1978. IABP was required for refractory shock following cardiopulmonary bypass (CB) in 53 patients, for preoperative cardiogenic shock after acute myocardial infarction (CSMI) in nine and was electively placed prior to CB in 13. Sixty-two patients (81%) were able to separate from CB with IABP and pharmacologic support and were assisted 24-432 hours (median 64 hours). Fifty-five (73%) were weaned from IABP. Fifty (67%) are hospital survivors; late deaths have occurred in six patients (8%). Hemodynamic effect of IABP was demonstrated by comparison of pumping 1:1 to 1:8 mode in five balloon-dependent patients after CB. IABP was found to decrease systolic blood pressure, left ventricular filling pressure and peripheral resistance (p < .05). It increased diastolic and mean blood pressure, cardiac index and the endocardial viability ratio (p < .05). The post-CB use of IABP resulted in highest salvage when utilized to support failing hearts that required surgery despite recent preoperative infarction or when intraoperative ischemic injury had occurred. Poorest results were in patients with extensive chronic myocardial damage. Except in the case of preoperative cardiogenic shock, it was impossible to establish statistically reliable criteria for patients in whom elective preoperative insertion was found to be necessary. Careful surgical and anesthesia management with good monitoring can be used instead of preoperative IABP in the majority of (if not all) hemodynamically stable patients regardless of risk classification.

Adult↗
PubMed1979

Late hemodynamic evaluation of Hancock Modified orifice aortic bioprosthesis.

Nineteen patients with Hancock Modified Orifice prosthesis (HMO-250), size 19 to 23 mm, were recatheterized 6 to 16 months following aortic valve replacement (AVR). Although hemodynamic characteristics varied widely, HMO-250 compared favorably to the standard model 243 (less than 0.05). Mean peak resting gradient across HMO-250 was 14.8 torr at rest and rose to 26.8 torr with exercise. Systolic gradients for HMO-250, both resting and exercise, were improved for 21 mm (p less than 0.01), but not for 23 mm. Increasing the patient's body surface area (BSA) correlated with increasing gradients for 23 mm (p less than 0.05), but was unrelated to 21 mm. Effective orifice areas were similarly found to be improved with 21 mm HMO-250 but unchanged for 23 mm. Use of the 21 or 23 mm size HMO for AVR is supported only when the patient's body surface area is less than 1.8 m2. If the body surface area is greater than 1.8 m2, annulus enlargement and a larger size bioprosthesis should be employed. Use of 19 mm porcine xenograft for AVR is not supported.

Aortic Valve Insufficiency↗
PubMed1978

Value of coronary bypass surgery. Controversies in cardiology: Part I.

The value of coronary bypass surgery has been studied carefully during the last decade. Four methods, none perfect, have been used to compare the results of such surgery with the results of medical therapy. New data are likely to be merely supportive rather than the outcome of a definitive study with a new and a acceptable experimental design. It is therefore time to analyze the available data in light of the treacherousness of the disease and to determine if a clear trend is evident. There appears to be sufficient evidence to state that properly performed coronary bypass surgery will increase coronary blood flow and relieve angina pectoris in 90 percent of patients; total relief of angina can be expected in 60 percent and partial relief in 30 percent. Compared with modern medical therapy, properly performed coronary bypass surgery appears to prolong the life of patients who have obstruction of the left main coronary artery or triple or double vessel disease. There is not adequate evidence to state that the procedure will prolong the life of patients with single vessel obstruction. However, patients with single vessel obstruction and unacceptable angina pectoris should be considered for bypass surgery (especially patients with obstruction of the left anterior descending coronary artery). In practice, at Emory University Hospital, Atlanta, bypass surgery is recommended for young people with few symptoms if compelling obstructing lesions are present and in older patients only if their symptoms require it. Medical therapy is given before and after bypass surgery. When bypass surgery is performed in an excellent fashion (operative risk 1 percent) a great deal of "controversy" about this problem vanishes.

Angina Pectoris↗
PubMed1978

Criteria for operability and reduction of surgical mortality in patients with severe left ventricular ischemia and dysfunction.

A series of 188 patients who were operated on for left ventricular ischemia and dysfunction is presented. Angina was a prominent symptom in all patients, and a history of congestive heart failure could be elicited in 20%. Mean ejection fraction for the series was 0.35, with 67% having an ejection fraction of 0.35 or less 24%, 0.20 or less. Complete revascularization was accomplished whenever possible; more than 70% of the patients had triple-vessel disease, and single bypass was performed infrequently (5%). Factors thought to be important in achieving a low operative mortality (2.1%) were: precise prebypass monitoring, particularly with the V5 precordial lead; maintaining a low rate-pressure product (less than 12,000) prior to bypass; myocardial preservation with cold hyperkalemic or hyperkalemic-hyperosmolar solution; and careful titration of inotropic and vasodilator drugs. Inotropic drugs and intraaortic balloon pumping were used frequently in this series. The late mortality was 4.3%. Angina was completely relieved or improved in 94% of the patients. Those having a history of congestive heart failure had an increased late mortality rate, four times that of the entire series.

Angina Pectoris↗
PubMed1978

Potassium-induced cardioplegia. Additive protection against ischemic myocardial injury during coronary revascularization.

Potassium-induced cardioplegia during anoxic arrest was utilized in a study of 190 consecutive patients undergoing revascularization (average 2.8 grafts per patient) from August, 1975, through August, 1976. Surgical technique, moderate systemic hypothermia with intermittent anoxic arrest, and the surgeon were the same for all patients. One hundred thirty-five patients (KC1-treated) received a bolus (150 ml.) of potassium solution injected into the proximal aortic root whenever the aortic cross-clamp was applied; 55 others served as control subjects. The mortality rate was 2.2% (three of 135) in the KCl-treated group and one of 55 in the control group. New Q waves appeared in 5.9% (eight of 135) of the KCl-treated patients and 11% (6 of 55) of control subjects (p = N.S.). Catecholamine drips were required after bypass in 4.4% (six of 135) of patients given potassium and 18% (10 of 55) of control patients (p less than 0.05). Profound myocardial relaxation was of added technical value with potassium. It is our impression that hearts treated with potassium exhibited more prompt cardioversion, separated from cardiopulmonary bypass with less need for inotropic support, and exhibited less myocardial injury during the revascularization procedure.

Cardiopulmonary Bypass↗
PubMed1978

Hemodynamic and clinical evaluation of the Hancock xenograft bioprosthesis of aortic valve replacement (with emphasis on management of the small aortic root).

One hundred twenty-nine consecutive patients underwent isolated aortic valve replacement with the Hancock porcine xenograft between July, 1974, and December, 1976. The hospital mortality rate was 3.9 percent. No patient was treated with anticoagulants, and valve-related complications were extremely rare. The smaller prosthetic sizes (19 and 21 mm. stent diameter) should be used with extreme caution, and the 19 mm. prosthesis should probably never be used in the audult patient. Two methods of managing the small aortic root are emphasized: one to avoid using the smaller prosthetic size in adults and the other to alter greatly the root size in children who have a hypoplastic aortic annulus. Acceptable calculated orifice sizes and left ventricular--aortic (LV-Ao) pressure gradients may be obtained with the 23 mm. or larger prostheses. Actuarial survival curves show 92 percent of patients alive and well at 24 months' follow-up.

Adolescent↗