Biological performance of TiNi shape memory alloy vascular ring prostheses: a two year study.

A method was developed for the noninvasive insertion of a vascular ring prostheses aimed at preserving arterial patency and preventing restenosis following angioplasty. Using a specially designed 7F catheter 22 nitinol (TiNi) wire prostheses (I.D. 5 mm; 0.25 mm thickness) were torsion reduced in diameter and inserted under fluoroscopy into both carotid (n = 2) and iliac-femoral arteries (n = 20) of dogs. Aspirin (650 mg BID) and Persantin (200 mg BID) were given for only 30 days postoperatively. Angiography of all rings at 1, 6, 12 months exhibited excellent biocompatibility and long term patency 91% (20/22) as reported in Trans ASAIO 32:30, 1986. Four rings inserted in the right and left common iliac arteries and femoral artery were followed for up to 2 years and exhibited 100% patency. Angiography demonstrated that the anchorage of the prostheses was stable and the lumen was uniformly covered by a thin neointimal layer of endothelial like cells. The prostheses were patent with no evidence of thrombosis or inflammation. In view of the problem of recurrent stenosis occurring during the healing period after balloon angioplasty (PTA or PTCA), this approach may lead to a new means of clinical intervention in atherosclerosis.

Titanium-nickel intravascular endoprosthesis: a 2-year study in dogs.

Twelve 5-mm-internal-diameter intravascular endoprostheses of noncorrosive, shape-memory titanium-nickel (TiNi) alloy were delivered transluminally by catheter and implanted in the iliac (n = 10) and femoral (n = 2) arteries of six normal dogs for either 1 or 2 years in order to evaluate the implantation technique and long-term effects. The patency rates were as follows: at 1 month, 92% (11/12); at 1 year, 100% 11/12 widely patent; 1/12 recanalized); and at 2 years, 100% (3/4 without stenosis; 1/4 with 20% stenosis). No migration, erosion, inflammation, surface thrombus, or stenosis of the side branches was seen; an absence of untoward angiographic and histopathologic effects was detected at 1 and 2 years. The neointima was completely endothelialized, without changes in thickness over time, 229.3 +/- 127.6 microns after 1 year and 223.3 +/- 216.7 microns after 2 years (p = not significant). The neointimal layer became thicker toward its distal aspect (p less than or equal to .05). Satisfactory delivery, long-term patency, and biocompatibility (manifested as a thin, stable neointima) were observed for the TiNi intravascular endoprosthesis at 1 and 2 years.

Chloroquine neuromyotoxicity. Clinical and pathologic perspective.

Six cases of toxic myopathy and/or neuropathy with chloroquine and/or hydroxychloroquine therapy are described. Two patients had unique clinical and pathologic evidence of cardiomyopathy secondary to chloroquine or hydroxychloroquine therapy. One patient had polyneuropathy secondary to chloroquine toxicity. This may be the first documentation of several features of chloroquine/hydroxychloroquine toxicity: morphologic changes in human peripheral nerve in chloroquine toxicity; chloroquine/hydroxychloroquine cardiomyopathy diagnosed by endomyocardial biopsy; and hydroxychloroquine myotoxicity. Chloroquine is a neuromyotoxin that affects nerves and cardiac and skeletal muscles. Discontinuation of chloroquine and hydroxychloroquine resulted in marked improvement in most cases. The reversibility of the symptoms emphasizes the importance of recognizing potential signs of nerve, muscle, and cardiac toxicity in patients being treated with chloroquine or hydroxychloroquine.

Comparison of stress digital ventriculography, stress thallium scintigraphy, and digital fluoroscopy in the diagnosis of coronary artery disease in subjects without prior myocardial infarction.

Exercise thallium scintigraphy is often used for the diagnosis of coronary artery disease (CAD). Exercise digital subtraction ventriculography and digital subtraction fluoroscopy are new diagnostic procedures with roles that have not been determined. To compare the relative accuracies of the digital techniques with thallium scintigraphy, 97 consecutive patients without myocardial infarction underwent all 3 tests on the day before their scheduled coronary angiograms. Forty-two patients had CAD (more than 50% diameter narrowing of 1 major artery). A fixed or reversible perfusion defect defined an abnormal thallium test response and a segmental wall motion abnormality at rest or with exercise defined an abnormal digital ventriculographic response. Any visualized coronary calcific deposit defined an abnormal digital fluorographic response. The sensitivities of digital fluoroscopy (86%) and digital ventriculography (79%) were significantly higher than the sensitivity of thallium (62%) (p less than 0.05). The specificity of thallium (82%) was not significantly higher than that of either digital ventriculography (72%) or fluoroscopy (67%). The diagnostic accuracies of digital fluoroscopy, digital ventriculography, and thallium were 75%, 75% and 73%, respectively. A logistic regression model showed that thallium and digital fluoroscopy were more accurate in younger patients, whereas digital ventriculography was more sensitive in hypertensive persons and in those not taking beta-blocking drugs. The choice of test depends on disease prevalence, clinical variables (such as age and hypertension) and the importance of functional information obtained from stress testing.

Captopril in congestive heart failure resistant to other vasodilators.

In an attempt to study the possible mechanism(s) by which captopril controls resistant heart failure, sequential haemodynamic studies (radioisotope technique) and humoral measurements (plasma renin activity, plasma aldosterone and plasma catecholamines) were obtained in 11 such patients. The studies were made at the time patients became unresponsive to other vasodilators (hydralazine or prazosin); the vasodilator drug was then discontinued and five days later, the 'no-vasodilator' studies were obtained. Captopril therapy was then started. Optimum daily maintenance dose of captopril varied from 75 to 200 mg in different patients. Studies were again repeated after a period of time equal to the duration of the previous vasodilator therapy. Digitalis and diuretic doses were kept constant throughout. Captopril improved effort tolerance in ten patients. Haemodynamically, mean blood pressure and peripheral resistance were lower than during vasodilator therapy (85 +/- 3.1 v. 92 +/- 3.3 mmHg and 47 +/- 4.4 v. 59 +/- 4.4 U.M2, respectively; p less than 0.05 for both). Cardiac index was higher during captopril treatment (1.95 +/- 0.15 v. 1.63 +/- 0.10 l/m2, p less than 0.01) and pulmonary mean transit was normalized by captopril (14.6 +/- 1.7 v. 18.4 +/- 1.3 s, p less than 0.05). Humoral indices revealed a significant (p less than 0.05) reduction in plasma aldosterone during captopril therapy (25.9 +/- 5.6 ng/dl during captopril, v. 62 +/- 22 ng/dl with no vasodilators and 50.9 +/- 6.1 ng/dl with other vasodilators). Moreover, there was a decrease in circulating plasma catecholamines during captopril treatment, but differences between the three treatment periods were not statistically significant.(ABSTRACT TRUNCATED AT 250 WORDS)

Selective coronary arteriography: a clinical comparison of two contrast agents.

The radiopacity and complications of meglumine iothalamate 52% and sodium iothalamate 26% (Vascoray) were compared with those of meglumine diatrizoate 66% and sodium diatrizoate 10% (Renografin -76) in 2258 patients with and without cardiac disease. There was no difference in radiopacity and the type and incidence of adverse reactions were similar, but the frequency was significantly higher (p less than 0.05) with Vascoray in patients with constrictive pericarditis, dissecting aortic aneurysm, and primary pulmonary hypertension. The difference in the frequency of hypotension, sinus bradycardia, and transient asystole in the Renografin -76 and Vascoray groups was statistically significant. Ventricular arrhythmias occurred in 6% of the patients with primary myocardial disease compared to an average of 0.7% in those without this cardiac abnormality (p less than 0.01), but there was no significant difference in the frequency in the two contrast agent groups. All reactions were treated and the studies were performed without mortality. Results of this study show that iothalamate formulation with sodium to meglumine ratio of 1:2 containing 410 mEq/L of sodium (Vascoray) is suitable and safe for clinical use for roentgenographic studies of the heart, and coronary artery circulation.

Thromboxane biosynthesis in platelets of diabetic and coronary artery diseased patients.

We have shown that platelets of diabetic patients (D) with coronary artery disease (CAD) produce more thromboxane A2 (TXA2) compared to normal subjects (N), when induced to aggregate with arachidonic acid. The purpose of this investigation was to determine: 1) whether TXA2 biosynthesis in platelets of D without exogenous substrate is increased, 2) whether platelets of D without CAD produce more TXA2 than N and 3) to compare platelet TXA2 biosynthesis in D with those angiographically diagnosed as having CAD but without D. TXB2 (stable metabolite of TXA2) was measured by RIA in platelets of 100 volunteer subjects: 24 D without other clinical complications, 10 D with retinopathy or nephropathy, 7 D with CAD, 30 CAD without D and 11 had D and hypertension. Eighteen subjects had no D, CAD or hypertension. TXA2 synthesis in platelets, stimulated to aggregate with both endogenous and exogenous substrate was higher in all patient classes studied as compared to normal subjects. Plasma triglyceride concentration was higher in diabetics as compared to controls while total cholesterol as well as platelet phospholipid fatty acid distributions were similar in all groups of subjects indicating a similar substrate concentration for TXA2 biosynthesis. It is concluded that platelets of D and CAD with or without D have greater sensitivity to aggregation which might be due to the increased thromboxane synthetase system at one or more sites.

Primary myocardial disease. Correlation with clinical findings, angiographic and biopsy diagnosis. Follow-up of 139 patients.

The purpose of this study was determination of the prognostic value of clinical and tissue (biopsy) findings of 139 patients with cardiomyopathy. The types of cardiomyopathy were congestive (113 patients) and hypertrophic or constrictive (26 patients). The mean follow-up period of all patients was 4.3 years. Follow-up of the survivors was between 13 months and 11.9 years, mean 5.4 years. Of the 47 cardiac deaths (33.8%), the minimum and maximum follow-up was two weeks and 7.5 years, respectively (mean 2.1 years). Patients with congestive heart failure had the highest five year cardiac mortality rate (51.8%). Coexisting cardiac arrhythmia had no influence on prognosis and an arrhythmia only was benign in most patients. Myocardial hypertrophy or fibrosis or both and myocardium with no pathologic diagnosis had prognostic value. Small-vessel disease was infrequent and not associated with specific clinical manifestations.

HDL-cholesterol concentration and severity of coronary atherosclerosis determined by cine-angiography.

We studied 226 adult male subjects (mean=52yr) who underwent coronary arteriography. Their serum lipid and lipoprotein levels [total cholesterol (TC), triglycerides (TG), HDL-cholesterol (HDL-C), LDL-C, HDL-phospholipid (HDL-P), HDL-TG, HDL-C/TC, HDL-P/TC, LDL-C/TC, LDL-C/HDL-C and LDL-C/HDL-P] were correlated with the severity of coronary artery disease (CAD). Studies showed a slight but statistically significant correlation (linear regression) between CAD and HDL-P/TC (r=-0.24, P < 0.001), HDL-C/TC (r=-0.20, P < 0.002), followed by LDL-C/HDL-P (r=0.19, P < 0.004) and HDL-P (r=-0.18, P < 0.008). HDL-C, LDL-C and TC were significant at the P < 0.05 level; P value of TG was non-significant. Subjects were conveniently grouped based on degree of coronary artery narrowing: normal, mild (1-50%); moderate-severe (51-99%) and very severe (100% occlusion). Of the 11 lipid variables, the best predictor of the stage of the CAD was HDL-P/TC as measured by one-way analysis of variance. This trend was unaltered even after adjustment for covariates. HDL-P, LDL-C/HDL-P and HDL-C/TC were also significant, but the other lipid parameters were not. The study indicates that HDL-C, by itself, is not as effective a predictor of CAD as HDL-P/TC. Also, the small but statistically significant inverse relationship between HDL-P/TC and CAD suggests that a low HDL-P/TC ratio can be considered a risk factor for CAD but not as a dependable clinical diagnostic aid for predicting the severity of CAD on an individual basis.

Cell-mediated cytotoxicity to cardiac cells of lymphocytes from patients with primary myocardial disease.

The etiology of primary myocardial disease is unknown. With the advent of immunologic technics, an immune process related to primary myocardial disease has been sought, but none has been elucidated as diagnostic or causative. The authors attempted to study the possibility of a cell-mediated component in the etiology of primary myocardial disease. Cell-mediated immunologic injury of cultured, human myocardial cells was studied in cells from patients with primary myocardial disease and controls by means of a 51chromium-release method. Significant lymphocytic cytotoxicity against myocardial cells was detected in cells from 23 (30%) of 73 patients with primary myocardial disease, compared with two (4%) of 49 normal, healthy control subjects. Significant cytotoxicity was also observed in cells from 36 (24%) of 148 patients who had other cardiac diseases, mainly rheumatic and atherosclerotic diseases. No group showed cytotoxicity against a long-term culture of Chang hepatic cells. No clinical correlation between the severity of the disease and increased cytotoxicity could be found. It is concluded that lymphocytic reactivity against myocardial cells probably results from myocardial damage due to a variety of causes, and that it is not specific for primary myocardial disease.

Fibrinolysis in familial pulmonary hypertension.

Although an autosomal dominant mode of inheritance has been documented for many cases of primary pulmonary hypertension, the pathogenesis of the disease remains unclear. A report of abnormal fibrinolysis in familial pulmonary hypertension has raised the possibility that the pathogenesis may be related to an impaired ability to lyse recurrent pulmonary microemboli. Primary pulmonary hypertension was diagnosed in three of ten members of a kindred. The pattern of inheritance was compatible with an autosomal dominant gene. Eight members of the kindred were available for study, one of whom has primary pulmonary hypertension. The results of coagulation studies, caseinolytic determinations of plasminogen and antiplasmin, and fibrinolytic titers of antiurokinase did not differ significantly from those of the control group. These findings suggest that a deficient fibrinolytic system is not the cause of primary pulmonary hypertension, although differences in methodology may explain our inability to demonstrate abnormal circulating fibrinolysis in this kindred.

Manual coronary endarterectomy. Clinical experience in 315 patients.

From July, 1970, to December, 1973, manual endarterectomies were performed on 330 coronary arteries in 315 patients. The procedures were performed on either an elective or nonelective basis. The over-all hospital mortality rate was 1.27 per cent. Postoperative myocardial infarction occurred in 4.8 per cent of these patients. Postoperative catheterization was performed on 186 endarterectomized arteries; the average time of postoperative catheterization was 13.1 months after surgery. The over-all patency rate was 76.3 per cent. This experience suggests that endarterectomy is a safe and useful adjunct to saphenous vein bypass grafting procedures when used in a restricted fashion as detailed in this presentation.