Another prosthetic heart valve?
Explore the source record for details and available documents.
Biomedical subjects
Publications and source records attributed to J R Pluth.
Explore the source record for details and available documents.
The initial experience with intra-aortic balloon assist (IABA) at the Mayo Clinic has been with 34 desperately ill individuals; 17 survived hospitalization. Hemodynamic improvement associated with institution of IABA can be documented. An unacceptably high complication rate (26%) has resulted in extensive modification in the technique of employing IABA. Concepts of patient selection and applications of IABA have evolved from this initial experience and from a review of the literature and have resulted in less reluctant use of this cardiac-assist modality.
A patient with constrictive pericarditis following an open-heart operation without sepsis is discussed. In the absence of sepsis, it has been widely held that this complication does not develop following an open-heart procedure. The fatal outcome in this patient could have been avoided had such an association been known.
Dobutamine, a recently introduced derivative of dopamine, is reported to retain inotropic properties with less pronounced chronotropic and arrhythmogenic effects than isoproterenol. The drug was evaluated in two doses, 5 mug/kg/min and 10 mug/kg/min, in two groups of ten patients each, during emergence from cardiopulmonary bypass. A third group of five patients was studied similarly with isoproterenol, 0.02 mug/kg/min. Cardiac index increased 16 and 28 per cent eith the two doses of dobutamine, respectively, and 9 per cent with isoproterenol. Heart rate, in contrast, increased 6 and 15 per cent with dobutamine (not significant) and 44 per cent with isoproterenol (significant). Dobutamine seemed to associated with fewer arrhythmias than isoproterenol. It is concluded that dobutamine, 5-10 mug/kg/min, is suitable for use during emergence from cardiopulmonary bypass and may possess advantages over isoproterenol.
The peak rate of systolic wall thickening (pdTw/dt) in regions of the left ventricle was determined by biplane roentgen videometry in 60 patients before and a median of 14 mo after aorto-coronary bypass graft surgery. The left ventricular ejection fraction, stroke volume, and end-diastolic volume and pressure did not change significantly after surgery in the presence of patent or occluded grafts (P greater than 0.05). Statistically significant increases occurred in the peak rate of systolic wall thickening regions supplied by patent bypass grafts, and significant decreases occurred in regions with occluded grafts (P less than 0.01). Of 42 preoperatively hypokinetic regions (pdTw/dt greater than 0 less than 5.0 cm/s) supplied by a patent graft, 30 improved by an average of 2.6 cm/s after operation; 18 returned to normal. Failure of 24 hypokinetic regions to improve to normal was associated with myocardial infarction in 11 or with late postoperative graft blood flows of less than 60 ml/min measured by videodensitometry, in 10. All seven preoperatively akinetic (pdTw/dt=0) or dyskinetic (pdTw/dt less than 0) regions did not improve after the operation despite the fact that, in five of the seven, coronary bypass flows were over 60 ml/min. All eight preoperatively hypokinetic regions supplied by coronary artery graft flows of less than or equal 40 ml/min failed to improve to normal after operation. All nine preoperatively hypokinetic regions supplied by coronary artery graft flows of over 60 ml/min improved to normal after surgery. Late postoperative coronary artery bypass graft flows, the functional status of the myocardium, the status and distribution of the native coronary circulation, and decreased regional function elsewhere in the ventricle must all be considered when regional left ventricular function is interpreted.
Isolated mitral valve replacement with the Starr-Edwards prosthesis has been performed on 657 patients at the Mayo Clinic during the 11 year period ending January, 1972. The most recent subset of that series comprised patients who received the Model 6120 prosthesis. In this group, the operative mortality rate was 9 per cent and the actuarial late death rate at 5 years was 20 per cent. This survival rate is a significant improvement over the natural history of severe mitral valve disease. Factors associated with operative deaths are large left artrial size, advanced functional class, and previous heart surgery. Variables associated with higher incidence of late deaths are large left atrial size, patient age at operation, and multivalve disease. Risk of thromboembolism is increased with large left atrial size, presence of left atrial thrombus, and inadequate anticoagulant therapy.
The total experience (154 patients) with ball-valve (Starr-Edwards) replacement of the tricuspid valve, alone and in combination, through Dec. 31, 1971, at the Mayo Clinic is reviewed. The early mortality rate with isolated tricuspid replacement was twice that for tricuspid replacement combined with replacement of other valves. Among patients receiving three valves, those with "functional'' tricuspid insufficiency and those who were in New York Heart Association (N.Y.H.A.) Class IV preoperatively had a higher early mortality rate. The early mortality rate for the total group was 28%. Of those surviving tricuspid plus mitral valve replacement, 70% were alive at 3 years; at latest follow-up, 94% of those surviving were functionally improved. Of those surviving triple valve replacement, 56% were alive at 3 years; at latest follow-up, 93% of those surviving were functionally improved. Previous cardiac surgery with residual tricuspid valve dysfunction and severe disability, as judged by N.Y.H.A. class, influenced the outcome adversely. The experience reported here provides a standard against which never prostheses can be compared.
The ionic equivalency of three calcium salts was tested in 15 patients undergoing cardiac surgery with extracorporeal circulation. Of the three salts tested (chloride, gluconate, gluceptate), only calcium chloride showed a reproducible and highly significant relationship between the increase in total calcium and the increase in ionic calcium. It is suggested that extracorporeal circulation may be one clinical situation in which use of a calcium electrode may be of major value. The marked distortion of plasma proteins and pH, the addition of large amounts of citrate, and the differences between various calcium salts indicate that it is probably not possible to predict ionic calcium with assurance and that direct measurement may be necessary for optimal therapy.
Review of 1,684 cases of isolated aortic or mitral valve replacement with a Starr-Edwards prosthesis demonstrated that the procedure provides improved life expectancy over that found in the natural history of valvular heart disease. Further improvement in results depends on continued reduction in operative and late mortality and in the incidence of thromboembolism. Advanced preoperative functional class, atrial or ventricular enlargement, a history of prior heart surgery, advanced age at operation and untreated valvular disease were among the factors related to increased early or late mortality. The data suggest that adequate anticoagulation, earlier performance of valve replacement and more complete repair of valvular dysfunction may increase survival rates.
Serial preoperative and postoperative electrocardiograms and vectorcardiograms were obtained in 500 patients undergoing saphenous vein aortocoronary artery bypass graft surgery. Evidence of transmural myocardial infarction was found early postoperatively in 67 patients (13 percent). Age and sex distributions, number of vessels diseased or vessels grafted, and preoperative and postoperative New York Heart Association functional classification (mean follow-up, 26 months) did not differ in the groups with and without infarction. Increased duration of cardiopulmonary bypass time (more than 120 minutes) was slightly greater in the group with infarction (P smaller than 0.05). Multivariate analysis revealed that 60 percent of patients in the group with infarction were identified by a 1st day serum glutamic oxaloacetic transaminase value greater than 100 U/liter; however, for each such patient identified, there was approximately one false positive result. Use of other values (creatine phosphokinase, cardiopulmonary bypass time and total anoxic rest time) did not improve discrimination. Twenty-five percent of all transmural infarctions occurred within the zone of myocardium supplied by a diseased ungrafted artery. In 32 patients with early evidence of transmural mycardial infarction in a zone of myocardium supplied by a grafted artery, postoperative angiography showed as many with patent as with occluded grafts. Of 154 patients in the group without infarction who had early postoperative graft angiograms, 30 (19 percent) had one graft occluded and yet no evidence of transmural infarction by our criteria. Therefore, early postoperative evidence of transmural myocardial infarction as defined in this study is an unreliable indicator of the status of the graft supplying the zone of infarction.
From February, 1971, through February, 1974, heart valves of 510 patients were replaced with cloth-covered Braunwald-Cutter prostheses. The data indicate that cloth encapsulation of the prosthetic cage is associated with a reduction in thromboembolic complications, particularly for mitral valves. Cloth wear on the distal strut, however, is not prevented by use of a Silastic poppet and appears to be a typical finding in aortic valves recovered or inspected after 3 months. Excessive poppet wear has also been noted in the aortic position; poppet embolization has occurred on 2 occasions, and a third patient was found, at the time of reoperation for periprosthetic leak, to have opppet wear sufficient to permit embolization. Although there have been no reports of clinical malfunction of the mitral prosthesis at the time of this writing, further long-term observation of these patients appears warranted.
Twenty-one patients with prosthetic cardiac valves successfully underwent transurethral prostatic resection at the Mayo Clinic. Temperature elevation in 4 patients was the only postoperative complication; in particular, neither congestive heart failure nor thromboembolic complications developed and there were no operative deaths. Preoperative evaluation and clinical management of potential complications are based on the recognition of the complications that are peculiar to these patients. Particularly important is the proper use of antibiotics and anticoagulants and avoidance of overloading the circulation with fluid from open prostatic venous sinuses.
The results in 578 patients who underwent a saphenous vein bypass graft operation (isolated SVBG) or a SVBG combined with other procedures (combined SVBG) from 1969 through 1972 were analyzed. The operative mortality rate was low (3 percent) for isolated SVBG but increased considerably for combined SVBG. The late mortality rate was also low (4 percent) for isolated SVBG and also increased markedly for combined SVBG. The operative mortality rate did not change in the group undergoing left ventricular aneurysmectomy or mitral valve surgery for postinfarction mitral insufficiency, whether or not SVBG was used; however, late results were better in both groups when SVBG was performed. Among all groups, patients with postinfarction mitral insufficiency or rheumatic mitral incompetence associated with coronary artery disease had the poorest outcome. Despite the operative and late deaths, patients undergoing SVBG with aortic valve replacement showed excellent results in the group of survivors.
In 397 cases, serum glutamic oxaloacetic transaminase (GOT) and creatine phosphokinase (CPK) values were determined on the first, second, and third days after aorta-coronary artery saphenous vein bypass graft operations. Electrocardiographic (ECG) or vectorcardiographic (VCG) evidence of postoperative transmural infarction was found in 48 cases. Multivariate analysis indicated that GOT and CPK concentrations on day 1 had substantial discriminatory value regarding infarction. Discrimination by GOT values was not significantly improved by addition of CPK. Of the 61 cases positive by GOT values measured 1 day postoperatively (greater than 100 U. per liter; normal smaller than 24), 32 (52 percent) were negative by ECG or VCG; of the 336 cases negative by GOT, 19 (6 percent) were positive by ECG or VCG. GOT and CPK values increased with the number of vessels grafted and with the use of ventricular rather than atrial vents. Total serum enzyme values lack specificty in diagnosis of transmural infarction after the saphenous vein bypass operation.
In a series of 500 consecutive patients undergoing aorta-coronary artery saphenous vein bypass surgery, operative mortality was 2.5% (1% with one-vessel disease, 2% with two-vessel disease, and 3% with three-vessel disease). Transmural myocardial infarction occurred within 30 days after operation in 67 cases (13%) and caused 10 of the 16 deaths in that period. Among 484 patients followed 1 to 58 months (median, 26 months), there have been 20 deaths. Of the 464 survivors, 65% had complete relief of angina, 24% were improved, and 11% were unimproved. In 162 patients who underwent postoperative graft angiography between 1 and 42 months after surgery, a strong positive relationship existed between clinical response and completeness of myocardial revascularization as defined by the presence of a patent graft to all major coronary arteries with greater than 50% stenosis. A similar relationship was found between postoperative multistage treadmill exercise response and completeness of myocardial revascularization. Thus, 82% of patients completely revascularized were asymptomatic at the time of postoperative graft visualization, and 91% had a negative treadmill exercise response.
A 9 year review of patients who underwent replacement of the aortic valve with the Starr-Edwards prosthesis indicates that the operative mortality rate for aortic valve replacement continues to decline. Thromboembolic complications have been markedly lessened in newer model valves. Surgical therapy is no longer seriously questioned as the appropriate management for symptomatic aortic valvular disease. The large majority of patients who survive surgery can expect to be rehabilitated to a highly functional existence, with longevity not unlike that of the general population. The Starr-Edwards prosthesis is a very satisfactory prosthesis for replacement of the aortic valve.
Explore the source record for details and available documents.
Explore the source record for details and available documents.