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Biomedical subjects

A Pichard

Publications and source records attributed to A Pichard.

At least 19 recordsLinked to original sources
PubMed1989

Probe "balloon on a wire" ultra-low-profile coronary catheter: results of PTCA in 107 patients.

A new low-profile "balloon-on-a-wire" angioplasty catheter, the Probe (USCI), was used in 107 patients over a 4-month period. Twenty-nine patients had stable angina, 59 had unstable angina, and 19 had had myocardial infarction (MI) 3 to 15 days prior to the procedure; 71 patients had single-vessel and 36 had multi-vessel disease. In this series, 57 lesions were defined as complex. Successful dilatation was defined as a residual stenosis of less than 30%. Of 132 non-total obstructions, 127 (97%) were successfully dilated. Two distal lesions could not be reached, two lesions could not be crossed by the balloon, and a distal lesion dilatation resulted in acute closure in one case. Of 19 total obstructions, 16 (84%) were successfully dilated (mean residual stenosis 23%). The wire tip was unable to cross the lesion in the three unsuccessful procedures. Seven complications occurred in the series, all involving non-total obstructions: closure of a distal vessel and a side branch caused no clinical symptoms or EKG changes; three local dissections were tacked back with repeat dilatation; and two longitudinal dissections caused no apparent reduction in luminal diameter. The Probe's low-profile and exceptional trackability enabled it to cross very tight lesions with minimal trauma to the vessel wall. The high degree of conformability of the PET balloon minimizes vessel straightening or sheer forces and appears to reduce the potential for dissection. The device may therefore extend the indications and ease of PTCA while reducing complications of the procedure.

Angiography↗
PubMed1986

Correlation of coronary angioscopic to angiographic findings in coronary artery disease.

An Olympus ultrathin fiberscope, 1.8 mm outer diameter, was inserted intraluminally into 11 stenoses of the left anterior descending and circumflex coronary arteries in 8 patients at coronary bypass surgery. Intraluminal views were obtained by coupling the angioscope to a color video camera and videotape recorder, and compared with preoperative coronary angiographic findings in right and left anterior oblique views. Atherosclerotic plaque was observed as yellow-white mass attached onto the luminal lining, which may be large enough to virtually obliterate the vascular lumen. Angioscopy provided a topographic view and cross-sectional picture of stenosis not observed by angiography. Single-plane angioscopic cross-sectional stenotic lumens correlated well (r = 0.90, p less than 0.001) with calculated angiographic luminal narrowings. However, with subtotal obstruction, lesion length must be assessed angiographically. Coronary angioscopy can be a useful adjunct to angiography by providing the added dimension of the true cross-sectional view of obstruction.

Coronary Angiography↗
PubMed1986

Acute effect of systemic versus intracoronary dipyridamole on coronary circulation.

Dipyridamole has been proposed as an ideal agent to evaluate coronary vascular reserve because it produces selective coronary vasodilation without systemic hemodynamic effect. The actions of intracoronary (IC) and intravenous (IV) dipyridamole on coronary blood flow and systemic hemodynamics were compared in 15 patients with chest pain syndrome and normal coronary arteries. They received IC dipyridamole, followed 10 minutes later by 0.5 mg/kg of IV dipyridamole. IC dipyridamole produced a 73% increase in coronary sinus flow without hemodynamic changes, except for a slight increase in pulmonary systolic and diastolic pressures. IV dipyridamole administration produced an additional 88% increase in coronary sinus flow, reaching 172% over baseline; it was also associated with a significant (p less than 0.01) increase in heart rate (78 +/- 14 vs 102 +/- 19 beats/min), cardiac index (4 +/- 0.7 vs 6.3 +/- 1.7 liters/min/m2), and pulmonary artery systolic (27 +/- 5 vs 34 +/- 7 mm Hg) and diastolic pressures (12 +/- 4 vs 19 +/- 7 mm Hg). These data suggest that the coronary vasodilatory effect seen after IV dipyridamole administration is related to mechanisms other than direct coronary vasodilation.

Adult↗
PubMed1985

Cardiac tamponade following percutaneous transluminal coronary angioplasty: four case reports.

Percutaneous transluminal coronary angioplasty (PTCA) has had complications related to dilating catheters and guide wires such as coronary artery dissection, spasm, rupture, and perforation. This report describes four patients who developed cardiac tamponade following PTCA, presumably from right ventricular (RV) perforation. All four received large doses of heparin during PTCA and three received antiplatelet therapy. In three cases, cardiac tamponade occurred several hours after PTCA. All patients did well following operative intervention and no patient required repair of a cardiac perforation. We postulate that impaired hemostasis in the presence of an otherwise inconsequential RV perforation causes tamponade. Three alternatives to provide standby pacing are proposed.

Adult↗
PubMed1984

Acute coronary hemodynamic response to cigarette smoking in patients with coronary artery disease.

The acute changes in coronary blood flow and coronary resistance that occur in response to cigarette smoking have not been accurately determined. To define the factors that affect this response, coronary sinus blood flow was measured in 16 patients (group I) with coronary artery disease and in 6 patients (group II) without angiographically detectable coronary disease. Seven patients (group IA) had severe (greater than or equal to 75%) proximal left coronary lesions and nine patients (group IB) had significant distal lesions with 50% or less proximal stenoses. Group I had a smaller overall increase (increases 1.6 +/- 5.3%) in coronary sinus blood flow than did group II (increases 7.7 +/- 6.1%) (p less than 0.05). Coronary resistance increased overall (increases 2.7 +/- 5.3%) in group I but decreased (decreases 2.4 +/- 3.4%) in group II (p less than 0.05). Patients in group IA had a highly significant increase in coronary resistance as compared with group IB (increases 7.0 +/- 4.2% versus decreases 0.9 +/- 2.6%) (p less than 0.001). Coronary sinus flow tended to decrease (decreases 1.2 +/- 4.6%) in group IA but to increase (increases 3.8 +/- 5.1%) in group IB (p = 0.06). It is concluded that smoking increases coronary resistance in patients with coronary artery disease. A greater impact is observed in patients with a severe proximal stenosis than in those with a distal stenosis. It is proposed that smoking increases coronary artery tone at the site of the stenosis, limiting the coronary flow response proportionally to the size of the affected vascular bed.

Adult↗
PubMed1983

Determinants of ventricular tachycardia in patients with coronary artery disease and ventricular aneurysm. Clinical, hemodynamic, and angiographic factors.

Many patients with coronary artery disease (CAD) in whom ventricular tachycardia (VT) develops have transmural scars or frank aneurysms. However, only a minority of patients with ventricular aneurysms go on to develop VT. To determine which factors are associated with the development of VT in patients with aneurysms, we retrospectively reviewed the records of 154 patients with CAD and segments of akinesia or dyskinesia, or both, on left ventriculography. Of the 154 patients, 85 had 24-hour Holter monitoring or 48 consecutive hours of continuous electrocardiographic monitoring in an intensive care unit within 6 months of catheterization. VT occurring at least 10 days after myocardial infarction (MI) or in the chronic phase was recorded in 19 patients (Group I); the remaining 66 patients did not have VT (Group II). The clinical, hemodynamic, and angiographic characteristics of these 2 groups showed no significant difference with respect to age, time from first transmural MI to catheterization, congestive heart failure (CHF), ejection fraction, or presence of dyskinesia. Patients with VT had significantly larger aneurysms and a higher prevalence of septal akinesia or dyskinesia. However, stepwise discriminant analysis revealed septal akinesia or dyskinesia to be the only independently significant variable distinguishing the 2 groups. Thus, septal involvement appears to be a major determinant of VT in patients with CAD and ventricular aneurysm.

Adult↗
PubMed1983

Association of coronary artery disease and valvular heart disease in Chile.

This study analyzes the prevalence of coronary artery disease (CAD) among patients with rheumatic valvular heart disease (VHD) in Chile. Coronary angiography was performed in all patients referred to cardiac catheterization with VHD who were over age 50 years and who had angina or ECG signs of ischemia. A total of 100 patients entered the study. Significant CAD (greater than 50% obstruction) was found in 14% of the cases: 7% in patients with mitral valve disease (MVD), 18% in aortic valve disease (AVD), and 21% in combined mitral and aortic valve disease (MAVD). Angina was present in 14% of the patients with MVD, 63% with AVD, and 53% with MAVD. Only 57% of patients with CAD had angina pectoris; 20% with angina had CAD. Hemodynamic parameters and left ventricular ejection fraction were not correlated with the presence or absence of CAD. We conclude that in patients with valvular heart disease, the incidence of CAD is lower in Chile than previously reported in the English literature. We confirmed the fact that angina is often not associated with CAD, and that CAD is often present in the absence of angina.

Aged↗