Coronary angioplasty in iatrogenic coronary artery stenosis.

Iatrogenic coronary artery stenosis as a serious complication of aortic valve procedures is a difficult condition to solve. We present a case in which both ostia were involved. As the patient refused reoperation, percutaneous transluminal coronary angioplasty (PTCA) was used.

Clinical and hemodynamic results of cardiac valve replacement with the Monostrut Björk-Shiley prosthesis.

Between May 1983 and April 1986, 318 patients underwent cardiac valve replacement with the Monostrut Björk-Shiley prosthesis. There were 136 aortic valve replacements, 128 mitral valve replacements, and 54 multiple replacements. A total of 373 valves were implanted. Associated procedures were done in 79 (25%) of the patients. Hospital (30-day) mortality rate was 5.6% (18 patients): 2.9% (n = 4) after aortic, 7.8% (n = 10) after mitrals and 7.4% (n = 4) after multiple valve replacement. Follow-up was obtained in all 300 operative survivors, for a total of 500 patient-years (mean 18 months). Actuarial survival rate, excluding operative deaths, at 4 years was 94.7% +/- 1.5% (mean +/- standard error of the mean). There were 16 thromboembolic episodes (3.2/100 patient-years). Freedom from all valve-related complications was 87% +/- 2.4% at 3 1/2 years. Neither valve thrombosis nor structural failure has been observed. Eighty percent of the patients are in New York Heart Association functional class I. Forty-two patients (26 with aortic and 16 with mitral valve replacement) underwent cardiac catheterization a mean of 6 1/2 months after the operation. In the aortic position, peak gradients were an average of 6.9 +/- 1.2 mm Hg. Mean systolic gradients were 12.4 +/- 6.3 mm Hg and did not increase with exercise. In the mitral position, end-diastolic gradients were an average of 2.1 +/- 2 mm Hg and mean gradients, 5.9 +/- 2 mm Hg. Discharge coefficient (estimated orifice area/geometric area) was 0.63 +/- 0.2 for the aortic and 0.53 +/- 0.2 for the mitral prostheses. Disc opening was maximal in most patients. These results indicate that the Monostrut prosthesis has a low rate of thromboembolic events, no structural failures or thrombotic obstructions and excellent hemodynamic performance, especially in the small aortic sizes (discharge coefficient for 19 and 21 mm valves, 0.77).

Dissociation between indices of pump performance and contractility in patients with coronary artery disease and acute myocardial infarction.

An analysis of ventricular performance comparing pump function and muscle function indices was performed in 13 patients with acute myocardial infarction, ten patients with normal coronary arteries, and 15 patients with coronary artery disease. Pump function was described by plotting left ventricular stroke work index as a function of left ventricular end diastolic pressure. This description provided a clear separation between normal patients, and surviving and nonsurviving patients with acute myocardial infarction. Values of contractile element velocity (VCE5 as an estimate of Vmax) did not separate between normals and surviving or nonsurviving patients with acute myocardial infarction. In 15 patients with acute coronary artery disease there was no correlation between values of VCE5 and the ventricular function curve. Changes in performance following the stress of ventriculography, angiotensin infusion, or isometric hand grip exercise also did not show any correlation between pump function and muscle function indices. It is concluded that pump function indices are a better indicator of ventricular performance in patients with acute myocardial infarction and coronary artery disease.

Development of myocardial beta-adrenergic receptor density and adenylate cyclase activity after human heart transplantation.

An increase in basal heart rate caused by a lack of vagal control and chronotropic supersensitivity to epinephrine has been shown in transplanted human hearts. Prejunctional and/or postjunctional origins for this supersensitivity have been suggested, the latter involving changes in the number of myocardial beta-adrenergic receptors or in the receptor adenylate cyclase system. To directly determine the time course of change, serial determinations were performed during the first 3 months after heart transplantation. The beta-adrenergic receptor density measured by iodine 125-labelled iodocyanopindolol binding in 61 endomyocardial biopsy specimens (a mean of 6.1 +/- 0.58 biopsies from each of 10 patients) showed great intraindividual and interindividual variability (56.6 +/- 6.8 fmol/mg protein) with no mean trend toward gradually changing receptor densities. Isoproterenol-stimulated adenylate cyclase activity measured in 33 biopsy specimens (a mean of 5.5 +/- 0.67 biopsy specimens from each of six patients) varied considerably (112.5 +/- 13.8 pmol cyclic adenosine monophosphate/mg protein/min), again with no definite tendency with regard to the development over time. The beta-adrenergic receptor densities showed no statistical correlation with the degree of rejection as assessed by histologic criteria and antimyosin ration. These results suggest that in the first 3 months after heart transplantation beta-adrenergic receptor density and adenylate cyclase responses to 10 mumol/L isoproterenol do not change and that beta-adrenergic receptor density in the transplanted myocardium does not seem to be affected by the degree of rejection.

Hemodynamic evaluation of the integral monostrut Björk-Shiley prosthesis in the aortic position.

Between May, 1983, and November, 1984, the new integral monostrut Björk-Shiley prosthesis was used for aortic valve replacement in 62 patients. The prosthesis is machined from a solid piece of cobalt alloy and has no welded joints. The traditional U-shaped outlet strut has been replaced by a projecting metal finger that holds the disc in place. The disc opens to 70 degrees and is convexoconcave. Successful transseptal heart catheterization was performed in 23 patients an average of 6 months following operation to evaluate the hemodynamic performance of the prosthesis. The mean peak-to-peak gradient was 7.73 +/- 7.49 mm Hg (+/- standard deviation). In five valves it was 0, and in only three was it higher than 15 mm Hg. Significant peak gradients were directly related to the valve index (valve area/body surface area). Mean systolic gradient at rest was 12.7 +/- 6.27 mm Hg and did not increase after exercise. Effective orifice areas were adequate, and the discharge coefficient ranged from 0.77 for the 21-mm prosthesis to 0.48 for the 29-mm prosthesis. Minimal regurgitation, which was washed out on the next systole, was observed with all sizes of the prosthesis. Disc opening was maximal (70 degrees) in all but one of the observed instances. Longer clinical follow-up is required, but the new integral monostrut Björk-Shiley prosthesis, with its important design changes and excellent hemodynamic performance, appears to be a promising aortic valve substitute.

Combined aortocoronary bypass and intraoperative transluminal angioplasty in left main coronary artery disease.

Transaortic intraluminal angioplasty of the left main coronary artery by Grüntzig's technique has been used intraoperatively in 4 patients who underwent multiple aortocoronary bypasses. Angiographic and clinical results were excellent in 3 of them. It is suggested that this combined technique be used to obtain more complete revascularization at the time of coronary artery bypass. The technique is easy to perform without x-ray facilities in the operating room, and it seems reasonable to assume that it may improve the myocardial blood supply of those areas irrigated by small arteries originating between the stenosed main trunk and other subsequent lesions.

Two-year follow-up after laser thermal balloon angioplasty (LTBA) in lower extremities: initial experience.

We describe the results obtained with the use of laser thermal balloon angioplasty (LTBA) in the treatment of atherosclerosis obliterans of the lower limbs in 37 patients (34 males, 3 females, mean age 58 +/- 9 years) with occlusive arterial disease (Fontaine stages II-IV) presenting 39 significant lesions. Immediate results and two years of clinical follow-up are analyzed. Initial ankle/brachial Doppler index was 0.51 +/- 0.17. Eighteen lesions were located in the iliac area (13 stenoses 2.3 +/- 1 cm and 5 occlusions 4.2 +/- 3 cm) and 21 lesions in the femoropopliteal area (5 stenoses 2.6 +/- 2 cm and 16 occlusions 5.7 +/- 3 cm). A percutaneous procedure was used in 38 cases. In only one case was femoral dissection needed. The laser source was argon in 26 cases and Nd-YAG in 13. Initial success was 85% (89% in iliac lesions and 81% in femoropopliteal lesions; 100% in stenoses and 70% in occlusions). The presence of occlusion (p less than 0.01) and/or calcium (p less than 0.05) negatively influenced the immediate results. No major complications were observed; seven (17%) minor complications occurred. Ankle/brachial Doppler index after treatment was 0.82 +/- 0.21. Cumulative clinical patency for successfully treated patients after two-year follow-up was 91%. LTBA thus represents an effective and less aggressive way of treating peripheral atherosclerosis obliterans. In spite of some limitations, it is useful in selected patients. The results of this study are very much like those in the literature for similar series and early experience.

Antiplatelet agents and their effect on complications during or soon after percutaneous transluminal coronary angioplasty.

In a retrospective study, during which 179 patients had undergone percutaneous transluminal coronary angioplasty (PTCA), the overall initial success rate fell suddenly and unexpectedly from more than 90% to 70.4%: 54.9% in patients not receiving antiplatelet therapy and 86.4% in patients treated orally with 300 mg triflusal three times daily or 300 mg acetylsalicylic acid plus 75 mg dipyridamole three times daily. The initial success rate was similar in patients with unstable (66.0%) and stable (77.6%) angina. The overall incidence of severe complications (mainly occlusion) was 16.2% and was significantly (P less than 0.01) greater in the patients not receiving antiplatelet therapy (23.1% versus 9.1%). There was no significant difference between incidence according to antiplatelet therapy used. It is concluded that antiplatelet therapy during the peri-angioplasty period (from 2 days before to 2 days after) may prevent periprocedural events in patients undergoing PTCA.

[Coronary fistula to the right ventricle in heart transplant patients as a complication of repeated endomyocardial biopsies]. / Fístula coronaria a ventrículo derecho en pacientes trasplantados cardíacos como complicación de las biopsias endomiocárdicas repetidas.

Ninety-six coronary angiographies of 30 orthotopic heart transplant recipients were studied. Eleven coronary artery fistulas to right ventricle were seen in 7 (23.3%) patients; five involved the left anterior descending artery, four the right coronary artery, and two the circumflex artery. All the coronary arterial fistulas appeared within the first year after transplantation, when endomyocardial biopsies were more frequent. In the review of the histologic samples, we found coronary arterioles greater than 0.15 mm of diameter in 3 of 7 patients with coronary arterial fistula; on the contrary, those were not found in any of the 69 histologic samples of 23 heart transplant patients without coronary fistula (p less than 0.001). Neither clinic nor hemodynamic abnormalities were seen in any patient during the follow-up. The coronary fistula had a benign course, with a tendency to decrease in size and to close spontaneously.

Cardiovascular responses to intrathoracic pressure variations in coronary disease patients: a computer simulation.

Several studies have suggested that the Valsalva maneuver may predispose potential lethal arrhythmias in patients with coronary artery disease, since this maneuver induces diminished coronary flow. On the other hand some studies have suggested that the Valsalva maneuver abruptly reduces determinants of cardiac oxygen demand, relieving angina pectoris. In order to study the variations of the myocardial oxygen supply-demand relation, during different applications of the maneuver, a mathematical model of the human cardiovascular system is presented. The model has been submitted to an evaluation process allowing the inclusion of a number of additional refinements to the mathematical model structures, and the obtaining of a reduced model in order to improve the computer time and parameter estimation of the simulation. The simulated output variables of the model correlate well with in vivo data obtained from ten patients with typical exertional angina pectoris studied during cardiac catheterization. The evaluation of the cardiac catheterization data has allowed the differentiation of two subsets of patients by the identification of two different coronary controllers. Computer simulation has permitted the analysis of the relative influences of the intrathoracic and intraabdominal pressure variations on the cardiovascular variables. Depending on the coronary control of the patients, the simulation results have shown that the myocardial oxygen supply-demand relation, calculated during the simulation of high intrathoracic pressures, long duration Valsalva maneuvers, or two consecutive maneuvers, gets values higher or lower than unity. These results suggest, respectively, beneficial or detrimental cardiac effects on the patients.