Frank J. Hildner

Quantification of coronary artery calcium using ultrafast computed tomography.

Ultrafast computed tomography was used to detect and quantify coronary artery calcium levels in 584 subjects (mean age 48 +/- 10 years) with (n = 109) and without (n = 475) clinical coronary artery disease. Fifty patients who underwent fluoroscopy and ultrafast computed tomography were also evaluated. Twenty contiguous 3 mm slices were obtained of the proximal coronary arteries. Total calcium scores were calculated based on the number, areas and peak Hounsfield computed tomographic numbers of the calcific lesions detected. In 88 subjects scored by two readers independently, interobserver agreement was excellent with identical total scores obtained in 70. Ultrafast computed tomography was more sensitive than fluoroscopy, detecting coronary calcium in 90% versus 52% of patients. There were significant differences (p less than 0.0001) in mean total calcium scores for those with versus those without clinical coronary artery disease by decade: 5 versus 132, age 30 to 39 years; 27 versus 291, age 40 to 49 years; 83 versus 462, age 50 to 59 years; and 187 versus 786, age 60 to 69 years. Sensitivity, specificity and predictive values for clinical coronary artery disease were calculated for several total calcium scores in each decade. For age groups 40 to 49 and 50 to 59 years, a total score of 50 resulted in a sensitivity of 71% and 74% and a specificity of 91% and 70%, respectively. For age group 60 to 69 years, a total score of 300 gave a sensitivity of 74% and a specificity of 81%. The negative predictive value of a 0 score was 98%, 94% and 100% for age groups 40 to 49, 50 to 59 and 60 to 69 years, respectively. Ultrafast computed tomography is an excellent tool for detecting and quantifying coronary artery calcium.

Ultrafast computed tomography-detected coronary calcium reflects the angiographic extent of coronary arterial atherosclerosis

Abstract This study demonstrates the potential of ultrafast CT quantification of coronary calcium to reflect the extent of atherosclerosis measured by coronary angiography. The findings are concordant with pathology studies that have also shown a close relation between the extent of coronary calcium and the extent of atherosclerosis.6 The usefulness of this technique in finding a population of asymptomatic subjects in whom aggressive risk factor modification would be cost-effective should be explored.

Thrombosis on Bjork-Shiley aortic valve prosthesis: Clinical, arteriographic, echocardiographic and therapeutic observations in seven cases

Abstract Seven patients with massive thrombosis on a Bjork-Shiley aortic valve prosthesis are described. This complication was documented in 5 percent of our patients with a Bjork-Shiley valve and occurred 3 to 19 months (mean 13 months) after insertion of the prosthesis. Only one patient had adequate anticoagulant therapy at the time of diagnosis. All patients had acute or subacute clinical deterioration. Anginal chest pain was the presenting symptom in four patients, and acute left ventricular failure in three. In all patients, the closing click of the Bjork-Shiley prosthesis was not heard, and new aortic systolic or diastolic murmurs were audible. Cardiac catheterization and aortic root cinearteriography were performed in five patients. Severe prosthetic regurgitation was found In four patients and mild regurgitation in one. Abnormal disc motion—fixation of the disc in the open position, abnormal limited opening of the disc or imperfect closure—was demonstrated in all arteriographic studies. Echocardiograms revealed an immobile disc in two patients. Five patients were surgically treated by thrombectomy and debridement of the prosthetic valve; the original prostheses were left in situ. Four of these patients are alive and one died. Two patients who did not undergo surgical treatment died. Thrombosis on the Bjork-Shiley aortic valve has a high fatality rate. Suspicion of this complication should be followed by emergency catheterization and surgery. In critically ill patients, surgery may be required even without angiography. The occurrence of this serious complication, mostly in patients with a normal coagulatory state, indicates the need for permanent anticoagulation in patients with a Bjork-Shiley aortic valve prosthesis.

Myocardial dysfunction associated with valvular heart disease

Abstract Seventy-one patients undergoing valve replacement surgery were studied before and after operation to determine change of clinical condition and ventricular contractility. Preoperatively, all patients had functional class III or IV disease (New York Heart Association classification) and 55 percent had myocardial dysfunction. Post-operatively, the condition of 86 percent of patients improved clinically by at least 1 functional class, but 56 percent of patients had myocardial dysfunction. Cardiac index and left ventricular end-diastolic pressures were closely related to changes in angiographically determined myocardial contractility. Neither patient age, sex, duration of cardiopulmonary bypass, residual uncorrected valve disease nor coronary artery disease alone determined the degree of impairment in left ventricular contractility. A high incidence of myocardial dysfunction was found pre- and postoperatively in this study. In 16 patients with pure mitral stenosis, 6 (38 percent) had left ventricular dysfunction preoperatively, demonstrating intrinsic myocardial disease, possibly chronic rheumatic myocarditis. The demonstration of postoperative myocardial contractile abnormalities in previously normal patients suggests an intraoperative cause, perhaps related to cardiopulmonary bypass. Postoperative dysfunction may (1) exist preoperatively and remain unchanged, (2) occur intraoperatively, or (3) exist in a latent form preoperatively but be aggravated by the stress of surgery. Without both pre- and postoperative microscopic examination of the myocardium in the same patient, it is impossible to determine which process is primary.

Cardiovascular effects of glucagon in man

Abstract Cardiovascular effects of an intravenous injection of glucagon, 3 mg., were studied in 8 subjects during cardiac catheterization. In each study a prompt effect was noted, with an increase in heart rate, cardiac output, right ventricular dp/dt and right ventricular and systemic systolic pressures. Right ventricular end-diastolic pressure and systemic vascular resistance decreased. It is concluded that glucagon exerts positive inotropic and chronotropic effects upon the heart in man. Further studies are required to determine its proper clinical role and mechanism of action.

Conversion of Supraventricular Tachyeardias with Rapid Atrial Stimulation

Rapid atrial stimulation (RAS) is a technic useful for converting the rapid ventricular response of atrial tachycardia, atrial flutter, or junctional tachycardia to a slower ventricular rate with normal sinus rhythm or atrial fibrillation. It is particularly useful when alternate methods such as DC cardioversion, carotid sinus massage, and drug therapy are either ineffective or undesirable. It is safe in patients with digitalis intoxication, does not require general anesthesia, documents atrial rhythm, and can be used repetitively without cumulative effects.RAS was performed 129 times in 87 patients (45 males; 42 females) whose ages ranged from 33 to 90 years (mean 67 years). There were no major complications. Overall, including both initial and repeat attempts, RAS successfully converted supraventricular tachycardia in 71% of cases and failed in 29%.

Hemodynamic comparison of endocardial pacing of outflow and inflow tracts of the right ventricle.

Abstract The hemodynamic effects of pacing the outflow tract of the right ventricle were compared to those of pacing the inflow tract of the right ventricle at identical rates over a wide range of rates in subjects with either normal or abnormal A-V conduction. The results demonstrate that the hemodynamic sequelae of pacing the outflow and inflow tracts of the right ventricle are essentially similar and do not differ statistically. This study offers additional evidence of the relatively unimportant role of ventricular asynchrony in the cardiac performance in man.

Myocardial function in patients with coronary artery disease

Abstract Left ventricular function curves were constructed in 42 patients (18 normal, 5 with myocardial disease and 19 with coronary artery disease) by determining the responses to graded infusions of angiotensin. The curves were compared to standard methods of hemodynamic evaluation. The patients with coronary artery disease were in a wide range of functional categories with no consistent correlation between anatomic changes (determined angiographically) and left ventricular function. However, an abnormal left ventricular end-diastolic pressure or left ventricular cineangiogram always meant poor function, but abnormal reserve could be detected when these two measures were normal. The angiotensin infusion test proved to be safe and rapid in patients with coronary artery disease and is valuable in the preoperative assessment of left ventricular function, since standard objective measurements may be misleading. It can also provide an objective measurement in the patient after operation.

Progression of coronary artery disease: Cinearteriographic and clinical observations in medically and surgically treated patients

Abstract The evolutionary pattern of occlusive coronary artery disease was studied by comparing coronary cinearteriographic findings in repeated catheterizations of 85 patients. Fifty-six percent of 16 medically treated patients with coronary artery disease were found to have progression of occlusive coronary artery disease in the repeated study. Patients who had progressive coronary artery disease were similar to those with nonprogressive disease in age and in duration and severity of disease. A history of hypercholesterolemia seemed to be more frequent among patients with progressive than in those with nonprogressive coronary artery disease. Other risk factors of coronary artery disease were found to be similarly frequent among patients with progressive and nonprogressive disease. Progression of occlusive coronary artery disease was associated with a greater deterioration of cardiac function. Cardiac index decreased significantly in patients with progressive disease, and did not change very much in patients with nonprogressive disease. Among the patients with progressive disease, two had a myocardial infarction between catheterizations, whereas none of those with nonprogressive disease had infarction. Electrocardiographic findings were similar in both groups of patients, except for new infarction changes in the patients with progressive disease who sustained an infarct. Seventeen percent of 65 patients who underwent aortocoronary saphenous vein graft bypass surgery were found in the second study (average interval 10.1 months) to have proximal occlusion of a distally grafted vessel with a patent graft. Progression of disease in nongrafted coronary arteries was found in 6 percent of the surgically treated group. Of four patients who had internal mammary artery implantation, two had progression of coronary disease in a repeat study. Conclusions regarding the evolution and progression of coronary artery disease should be drawn only from medically treated patients, since coronary artery surgery may alter the natural course of this disease. Medically treated patients who are reconsidered for surgical treatment should have a repeat catheterization to detect any change in distribution of occlusive coronary artery disease and in cardiac function.

Disc Variance of Beall Mitral Valve

Abstract Disc variance in Beall mitral prostheses in 5 patients is reported. All 5 showed disc deformity. Erosion of the Teflon covering of the cage struts was present in varying degrees in 4 of the 5 patients. Disc grooving was present as early as sixteen days after operation. Severe thinning and notching of the disc were noted at autopsy in 3 patients who survived two years following prosthetic valve operation. In I of these two-year survivors the disc destruction was so extensive that incompetence developed; the valve failure contributed to the patients death. Disc variance must be anticipated in patients with Beall mitral prostheses inserted prior to March of 1968, when the valve fabrication was changed.