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Biomedical subjects

I Kronzon

Publications and source records attributed to I Kronzon.

At least 19 recordsLinked to original sources
PubMed1992

Observations of coronary flow augmentation and balloon function during intraaortic balloon counterpulsation using transesophageal echocardiography.

The intraaortic balloon pump has been shown to decrease myocardial oxygen demand by afterload reduction, while increasing myocardial oxygen supply by diastolic augmentation of coronary blood flow. This diastolic augmentation of coronary flow has been demonstrated experimentally with invasive methods. Noninvasively, transesophageal echocardiography has demonstrated efficacy in enabling visualization of the proximal left coronary artery and in recording coronary blood flow velocity. To assess the potential of this technique in demonstrating quantitatively the increase in coronary flow during counterpulsation, 6 patients were studied during intermittent balloon pumping. Peak diastolic coronary blood flow velocity increased by a mean of 117% (range 62 to 287) during balloon inflation (p = 0.002). Furthermore, coronary flow velocity integral increased by a mean of 87% (range 43 to 176; p = 0.003). Problems associated with intraaortic balloon pumping were discovered by transesophageal echocardiography in 4 patients (incorrect balloon placement, damage to the aortic wall [2 patients], and premature balloon deflation time). Transesophageal echocardiography can be used in evaluating intraaortic balloon positioning within the aorta and in monitoring coronary artery flow augmentation during counterpulsation. This relatively noninvasive technique adds another dimension to the evaluation of balloon function and may help in optimizing the benefits of counterpulsation.

Aged↗
PubMed1992

Surgical implications of transesophageal echocardiography to grade the atheromatous aortic arch.

Stroke is an especially serious complication of cardiopulmonary bypass with an incidence of 2% to 5%. This prospective study used transesophageal echocardiography (TEE) in 97 patients more than 65 years of age (mean age, 73 years) to identify those at high risk for aortic atheroemboli. The atheromatous disease of the aorta was graded by TEE: grade I = minimal intimal thickening (n = 29); II = extensive intimal thickening (n = 33); III = sessile atheroma (n = 15); IV = protruding atheroma (n = 10); V = mobile atheroma (n = 10). Clinical evaluation was also performed by intraoperative aortic palpation. Four patients who were graded as having normal aortas by palpation had intraoperative strokes. In contrast, 3 of these 4 patients were in grade V on TEE. The relationship of TEE to incidence of stroke was statistically significant (p less than 0.006), whereas there was no significant correlation between clinical grade and stroke incidence. Four of 10 TEE grade V patients were treated with hypothermic circulatory arrest and aortic arch debridement, and none suffered strokes. The other 6 patients were treated with standard techniques, and 3 had strokes. These results suggest that patients with mobile atheromatous disease are at high risk for embolic strokes that are not predicted by routine clinical evaluation. Selective use of circulatory arrest in the presence of TEE-detected mobile arch atheromas may reduce the risk of intraoperative stroke.

Aged↗
PubMed1992

Protruding aortic atheromas predict stroke in elderly patients undergoing cardiopulmonary bypass: experience with intraoperative transesophageal echocardiography.

Protruding atheromas of the aortic arch identified by transesophageal echocardiography have been implicated as a cause of stroke in elderly patients. One hundred thirty patients greater than or equal to 65 years of age were studied with intraoperative transesophageal echocardiography to detect aortic arch protruding atheromas and determine if these patients were at higher risk for perioperative stroke. Protruding atheromas were identified in 23 (18%) of 130 patients. In 19 (83%) of these 23 patients, palpation of the aortic arch at operation did not identify significant abnormalities. Five patients (4%) had perioperative stroke. Logistic regression identified aortic arch atheroma as the only historical or procedural variable that was predictive of stroke (odds ratio 5.8, 95% confidence interval 1.2 to 27.9, p less than 0.03). A history of peripheral or cerebrovascular disease, presence of aortic calcification, cardiac risk factors, age and duration of cardiopulmonary bypass did not predict stroke. In contrast, patients with protruding atheromas with mobile components were at highest risk. There were 3 (25%) of 12 patients with a mobile atheroma who had a stroke versus 2 (2%) of 118 patients without a mobile atheroma (chi-square = 10.3, p = 0.001). Displacement and detachment of the frail, protruding atherosclerotic material by aortic arch cannulation or by the high pressure jet emanating from the cannula tip may play an important role in the creation of embolization and stroke.

Aged↗
PubMed1992

The alternation between atrial flutter and atrial fibrillation.

Atrial fibrillation and atrial flutter share a common reentrant mechanism. However, the relationship between these arrhythmias has not been systemically studied to date. To evaluate the degree to which these arrhythmias may alternate, consecutive Holter monitor recordings which showed fibrillation or flutter in 96 patients were reviewed. One half of the patients were studied after open-heart surgery and the other half for varying indications. One quarter of the patients had atrial flutter in addition to fibrillation, and this alternation with flutter was significantly associated with the use of a type 1A antiarrhythmic drug (p = 0.007), but not with the use of digoxin or beta blockers (p = NS for both). Furthermore, this alternation with flutter was more common in the postoperative group (p = 0.01). A history of embolization was less common in patients who were in the postoperative group (p = 0.003) and patients who had flutter in addition to fibrillation (p = 0.05).

Adolescent↗
PubMed1992

Silent maladie de Roger.

A patient with no cardiac murmur was found to have a ventricular septal defect by Doppler echocardiography yet no evidence of pulmonary or right ventricular hypertension. This array of findings is distinctly unusual and appears to be at odds with the clinical teachings concerning small ventricular septal defects.

Adult↗
PubMed1992

Experience with twenty-eight cases of systolic anterior motion after mitral valve reconstruction by the Carpentier technique.

Systolic anterior motion of the mitral valve with left ventricular outflow tract obstruction after Carpentier-type mitral reconstruction with ring annuloplasty has led some surgeons to abandon an otherwise successful repair or to avoid use of a rigid ring. To assess the long-term significance of such motion, we studied 439 patients undergoing Carpenter mitral reconstruction at our institution between March 1981 and June 1990. The hospital mortality rate was 4.8% (21/439) overall and 3.7% (9/243) for isolated mitral reconstruction. Systolic anterior motion was found in 6.4% (28/438) after the operation, and 2.3% (10/438) had a coexisting left ventricular outflow tract gradient (mean 53 mm Hg). Of the 28 patients with systolic anterior motion, 27 (96.4%) had leaflet prolapse, 17 (60.7%) had undergone more than a 3 cm resection of the posterior leaflet, and two (7.1%) had preexisting idiopathic hypertrophic subaortic stenosis. All patients were treated medically, 14 with negative inotropic agents. Follow-up echocardiograms at a mean of 32 months demonstrated the disappearance of systolic anterior motion in 13 of 28 patients (46.4%) and resolution of the outflow tract gradient in 10 of 10 (100%). At follow-up only one patient was in New York Heart Association class III or IV and required reoperation for rheumatic mitral insufficiency. These data demonstrate that systolic anterior motion after Carpentier mitral reconstruction with ring annuloplasty is not prevalent and should be managed medically in most cases. Associated left ventricular outflow tract obstruction resolves with medical treatment.

Cardiac Surgical Procedures↗
PubMed1991

Protruding atheromas in the thoracic aorta and systemic embolization.

OBJECTIVE: To determine whether protruding atheromas in the thoracic aorta are a risk factor for systemic embolization. DESIGN: Case-control study. SETTING: A referral hospital. PATIENTS: A total of 122 patients with a history of stroke, transient ischemic attack, or peripheral emboli and an equal number of age- and sex-matched control patients. MEASUREMENTS: Evaluation using transesophageal echocardiography was done in case patients to detect protruding atheromas in the thoracic aorta and in control patients for cardiac indications other than emboli. MAIN RESULTS: Matched logistic regression showed that the presence of protruding atheromas was strongly related to the occurrence of embolic symptoms (odds ratio, 3.2; 95% Cl, 1.6 to 6.5; P less than 0.001). Furthermore, atheromas with mobile components were present only in case patients. When known risk factors for stroke (hypertension and diabetes) were added to the model, the presence of protruding atheromas remained an independent risk factor for embolic symptoms (odds ratio, 3.8). Hypertension was also independently associated with embolic symptoms (odds ratio, 2.7), but diabetes was not (odds ratio, 1.0). CONCLUSION: Protruding atheromas in the thoracic aorta can be detected by transesophageal echocardiography and should be considered as a cause of strokes, transient ischemic attacks, and peripheral emboli.

Aorta, Thoracic↗
PubMed1991

Congestive heart failure, coronary events and atherothrombotic brain infarction in elderly blacks and whites with systemic hypertension and with and without echocardiographic and electrocardiographic evidence of left ventricular hypertrophy.

Hypertension was present in 50% of 196 blacks and in 36% of 382 whites (p less than 0.001). A prospective study of 84 elderly blacks (70% women) and 326 elderly whites (73% women) with hypertension correlated echocardiographic and electrocardiographic left ventricular (LV) hypertrophy with incidences of congestive heart failure (CHF), coronary events and atherothrombotic brain infarction (ABI). Echocardiographic LV hypertrophy (p less than 0.02) and concentric LV hypertrophy (p less than 0.001) were more prevalent in hypertensive blacks than in hypertensive whites. Hypertensive blacks were younger (78 +/- 9 years) than hypertensive whites (82 +/- 7 years) (p less than 0.001). Other coronary risk factors were similar, except for higher serum triglycerides in whites than in blacks (p less than 0.02). Follow-up was 37 +/- 18 months in blacks and 43 +/- 18 months in whites (p less than 0.01). Incidences of CHF and coronary events were not significantly different in blacks and whites. ABI incidence was 38% in blacks and 21% in whites (p less than 0.005). Multiple logistic regression analysis showed that prior CHF (p = 0.000), concentric LV hypertrophy (p = 0.018) and echocardiographic LV hypertrophy (p = 0.022) were independent risk factors for CHF. Echocardiographic LV hypertrophy (p = 0.001), serum total cholesterol (p = 0.002), concentric LV hypertrophy (p = 0.005) and prior coronary artery disease (p = 0.042) were independent risk factors for coronary events. Prior ABI (p = 0.001), echocardiographic LV hypertrophy (p = 0.001) and electrocardiographic LV hypertrophy (p = 0.034) were independent risk factors for ABI.

Aged↗
PubMed1991

Transesophageal echocardiography is superior to transthoracic echocardiography in the diagnosis of sinus venosus atrial septal defect.

The purpose of this study was to compare transthoracic and transesophageal echocardiography in the diagnosis of various types of atrial septal defects. Forty-one adult patients with the clinical diagnosis of atrial septal defect were studied by transthoracic and transesophageal echocardiography (30 women, 11 men; 18 to 81 years of age). Transthoracic echocardiography demonstrated the atrial septal defect in 33 patients (secundum type in 28, primum type in 3 and sinus venosus type in 2). Transesophageal echocardiography demonstrated the defect in all 41 patients. Thus, in 8 (20%) of 41 patients the atrial septal defect was demonstrated by transesophageal and not by transthoracic echocardiography. Six of the eight had a sinus venosus type atrial septal defect; the other two patients had a secundum atrial septal defect (one of these two had a technically poor transthoracic echocardiogram and the other had a small atrial septal defect). Transthoracic echocardiography, therefore, failed to demonstrate the sinus venosus defect in six (75%) of eight patients. An anomalous venous connection associated with the sinus venosus defect was visualized by transesophageal echocardiography in seven of the eight patients but was not seen on transthoracic echocardiography in any patient. Sinus venosus type atrial septal defects are frequently not visualized in adults by conventional transthoracic echocardiography. Transesophageal echocardiography is recommended when an atrial septal defect is clinically suspected but cannot be visualized by transthoracic echocardiography.

Adult↗
PubMed1991

Prevalence of coronary risk factors in elderly blacks and whites.

Coronary risk factors were determined in a prospective study of 1,414 elderly persons (999 women and 415 men), mean age 82 +/- 8 years. Of 1,414 persons, 215 (15%) were black and 1,140 (81%) were white. The prevalences of cigarette smoking, hypercholesterolemia, low serum high-density lipoprotein cholesterol, and increased serum total cholesterol/high-density lipoprotein cholesterol ratio were not significantly different in elderly blacks and whites. Elderly blacks had a higher prevalence of hypertension (50% versus 36%, P less than 0.001), diabetes mellitus (27% versus 19%, P less than 0.01), and obesity (11% versus 5%, P less than 0.005) and a lower prevalence of hypertriglyceridemia (9% versus 15%, P less than 0.05) than elderly whites. In elderly persons with hypertension, electrocardiographic left ventricular hypertrophy occurred in 19% of blacks and 14% of whites (P not significant), echocardiographic left ventricular hypertrophy occurred in 72% of blacks and 56% of whites (P less than 0.01), and concentric left ventricular hypertrophy occurred in 60% of blacks and 39% of whites (P less than 0.001).

Aged↗