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Biomedical subjects

H R Phillips

Publications and source records attributed to H R Phillips.

At least 73 records · Page 4Linked to original sources
PubMed1988

Survival and cardiac event rates in the first year after emergency coronary angioplasty for acute myocardial infarction.

One year survival and event-free survival rates were analyzed in 342 patients with acute myocardial infarction who were consecutively enrolled in a treatment protocol of early intravenous thrombolytic therapy followed by emergency coronary angioplasty. Ninety-four percent of the patients achieved successful reperfusion, including 4% with failed angioplasty whose perfusion was maintained by means of a reperfusion catheter before emergency bypass surgery. The procedural mortality rate was 1.2% and the total in-hospital mortality rate was 11%. Ninety-two percent of surviving nonsurgical patients who underwent repeat cardiac catheterization were discharged from the hospital with an open infarct-related artery. The related cumulative 1 year survival rate for all patients managed with this treatment strategy was 87%, and the cardiac event-free survival rate was 84%. The 1 year survival for hospital survivors was 98% and the infarct-free survival rate was 94%. Multivariable analysis identified the following factors as independent predictors of subsequent cardiovascular death: cardiogenic shock, greater age, lower ejection fraction, female gender and a closed infarct-related vessel on the initial coronary angiogram. Among patients with cardiogenic shock, despite a 42% in-hospital mortality rate, only 4% died during the first year after hospital discharge. Similarly, the in-hospital and 1 year postdischarge mortality rates were 19 and 4%, respectively, for patients with an initial ejection fraction less than 40, and 25 and 3%, respectively, for patients greater than 65 years. An aggressive treatment strategy including early thrombolytic therapy, emergency cardiac catheterization, coronary angioplasty and, when necessary, bypass surgery resulted in a high rate of infarct vessel patency.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1988

Administration of thrombolytic therapy in the community hospital: established principles and unresolved issues.

In patients with acute myocardial infarction presenting to community hospitals, thrombolytic therapy should be initiated as rapidly as possible under the supervision of a physician. Paramedic or nurse-initiated pre-hospital therapy is currently investigational. Each hospital must have a detailed evaluation and treatment protocol for acute myocardial infarction that specifies the timetable for patient evaluation, who should or should not receive thrombolytic therapy and the proper dose and mode of administration of the agent or agents to be used. Monitoring after the administration of thrombolytic therapy should focus on arrhythmias, hemodynamic problems, recurrent ischemia and bleeding. The role of early cardiac catheterization to detect patients who have unsuccessful thrombolysis or who require mechanical revascularization procedures is under active investigation. The design of the Thrombolysis and Angioplasty in Acute Myocardial Infarction (TAMI) 5 study, which addresses the role of acute interventional catheterization in the treatment of patients with acute myocardial infarction, is described.

Angioplasty, Balloon↗
PubMed1988

Transluminal intracoronary reperfusion catheter: a device to maintain coronary perfusion between failed coronary angioplasty and emergency coronary bypass surgery.

The reperfusion catheter is a 4.3F catheter with 30 holes over its distal 10 cm. It is used to maintain coronary blood flow in patients awaiting emergency coronary bypass surgery after failed coronary angioplasty. The insertion of the reperfusion catheter was attempted in 20 patients (14 with total occlusion and 6 with severe residual stenosis judged to be in jeopardy of reclosure before operation). The reperfusion catheter was successfully placed across the obstruction in 18 patients (90%). After successful insertion of the reperfusion catheter, 16 patients had good anterograde flow (Thrombolysis in Myocardial Infaction [TIMI] trial grade II or III); angiographic improvement was associated with significant lessening of ST segment elevation as well as a decrease in chest pain in most patients. Two patients had poor or absent anterograde flow (TIMI grade O or I) because of extensive preexisting intracoronary thrombosis; one died from refractory ventricular fibrillation. In each of the remaining patients emergency coronary bypass surgery was performed with no deaths or significant cardiac complications. The reperfusion catheter is a safe and effective method to reestablish and maintain coronary blood flow before coronary bypass surgery after failed coronary angioplasty. Because there is the potential risk of serious complications, particularly thrombus formation within this catheter, the reperfusion catheter should be used cautiously and the patient should undergo immediate bypass surgery.

Angioplasty, Balloon↗
PubMed1988

Peripheral artery atherectomy: description of technique and report of initial results.

Percutaneous transluminal atherectomy has been developed for treatment of peripheral artery stenoses. The atherectomy catheter is inserted through a sheath, and the resection window of the catheter is positioned adjacent to the vascular stenosis. The balloon is inflated, and the motor-driven cutting blade advanced. The balloon is then deflated, the catheter withdrawn, and the atheromatous material, which resembles the resected material of an endarterectomy, removed from the catheter. This process is repeated until the resection provides an adequate lumen. To date, 12 arterial lesions (three common iliac, two external iliac, four superficial femoral, and three popliteal artery) in ten patients have been resected with excellent angiographic results. The conditions of seven patients who underwent atherectomy for relief from claudication were improved by the criteria of ankle/arm ratios and/or claudication distance. Three patients successfully underwent atherectomy for limb salvage. More data on long-term patency and restenosis rates are needed before the ultimate role of atherectomy in the management of peripheral artery disease can be determined.

Adult↗
PubMed1988

Coronary perfusion during acute myocardial infarction with a combined therapy of coronary angioplasty and high-dose intravenous streptokinase.

Two hundred and sixteen patients with acute myocardial infarction were treated with immediate infusion of high-dose (1.5 million units) intravenous streptokinase followed by emergency coronary angioplasty. The infarct lesion was crossed and dilated in 99% and persistent coronary perfusion after the procedure was achieved in 90% (including 3% with significant residual stenosis). Total in-hospital mortality was 12%. Multivariable analysis showed a higher hospital mortality with cardiogenic shock (41% vs 5% without shock), older age, lower left ventricular ejection fraction, and female sex. Final patency of the infarct-related vessel was determined by follow-up in-hospital cardiac catheterization. Coronary reocclusion occurred in 11% (symptomatic in 7%, treated with emergency angioplasty or bypass surgery; silent in 4%, treated medically). Of the surviving patients with successful initial establishment of infarct vessel patency, 94% were discharged from the hospital with an open infarct artery or a bypass graft to the infarct vessel. There was significant improvement in both ejection fraction (44% to 49%; p less than .0001) and regional wall motion in the infarct zone (-3.0 SD to -2.4 SD; p less than .0001) among patients with persistent coronary perfusion and insignificant residual stenosis at the time of the follow-up cardiac catheterization. Thus, a treatment strategy for acute myocardial infarction that includes immediate administration of streptokinase followed by emergency coronary angioplasty, and coronary bypass surgery when necessary, results in a high rate of early and sustained patency of the infarct-related vessel.

Angioplasty, Balloon↗
PubMed1988

Myocardial protection during coronary angioplasty with an autoperfusion balloon catheter in humans.

An autoperfusion balloon catheter was developed to allow passive myocardial perfusion during inflation through a central lumen and multiple side holes in the shaft proximal and distal to the balloon. We report its safety and efficacy in 11 patients undergoing elective angioplasty to a single coronary lesion. Each lesion was dilated three times with the autoperfusion inflation bracketed between two inflations by standard angioplasty catheters. Chest pain score, 12-lead electrocardiogram, heart rate, and mean aortic pressure were recorded before each inflation and at 1-minute intervals after inflation. Inflation duration during autoperfusion angioplasty (513 +/- 303 seconds) was longer than for the pre- (107 +/- 55 seconds, p = 0.0004) and post- (139 +/- 71 seconds, p = 0.0006) standard dilatations. The maximum ST-segment elevation and depression in any lead during autoperfusion angioplasty (0.3 +/- 0.5 and 0.6 +/- 0.8 mm) was significantly less than for the pre- (2.4 +/- 1.7 mm, p = 0.002 and 2.2 +/- 1.3 mm, p = 0.0004) or post- (1.9 +/- 1.3 mm, p = 0.002 and 1.6 +/- 1.3 mm, p = 0.018) standard dilatations at the same point in time. Maximal chest pain score during autoperfusion (3.2 +/- 3.5) was lower than for the pre- (6.1 +/- 2.1, p = 0.003) but not the post- (5.2 +/- 3.1, p = 0.07) standard angioplasty. All 11 patients underwent successful, uncomplicated procedures. We conclude that this autoperfusion catheter significantly reduces ischemic symptoms and signs during coronary angioplasty, allowing prolonged periods of balloon inflation.

Angioplasty, Balloon↗
PubMed1988

The risk for systemic embolization associated with percutaneous balloon valvuloplasty in adults. A prospective comprehensive evaluation.

STUDY OBJECTIVE: To prospectively investigate the evidence for embolic phenomena associated with percutaneous mitral and aortic valvuloplasty. DESIGN: Prospective, consecutive case series before and after balloon valvuloplasty. SETTING: Referral center hospital and cardiac catheterization laboratory. PATIENTS: Consecutive sample of 32 patients having balloon valvuloplasty for critical symptomatic stenosis of the mitral or aortic valve. Twenty-six patients had aortic stenosis; 6 had mitral stenosis. INTERVENTION: Computed tomography of the head, funduscopy, and electrocardiography were done in all patients before and after valvuloplasty. Cardiac isoenzymes were measured serially in 19 patients. MEASUREMENTS AND MAIN RESULTS: Previous cerebral infarction was seen in nine patients, with three showing a new abnormality after aortic valvuloplasty. In one of these patients a funduscopic hemorrhage was detected by photography. Total creatinine kinase and MB fraction were elevated in 1 of 19 patients. Serial electrocardiograms were unchanged in all patients. CONCLUSIONS: The incidence of cerebral neurologic events and myocardial injury are acceptably low after balloon valvuloplasty of calcific aortic and mitral stenosis. Both episodes of symptomatic cerebral infarction occurred in patients with apparent bicuspid aortic valvular stenosis, suggesting that calcific bicuspid aortic stenosis may be associated with more neurologic events after aortic valvuloplasty.

Adult↗
PubMed1988

Hemodynamic effects of intravenous pirmenol.

The hemodynamic effects of intravenous pirmenol were studied in 21 subjects instrumented with peripheral arterial, pulmonary artery, and left ventricular catheters. Baseline measurements of heart rate, cardiac output, pulmonary artery pressure, systemic arterial pressure, left ventricular end-diastolic pressure, left ventricular stroke work, and ejection fraction were obtained. An infusion of pirmenol hydrochloride was administered and hemodynamic measurements were repeated an average of 16.1 minutes following the start of the infusion after a new stable hemodynamic state was achieved. Significant increases in heart rate and systemic arterial pressure were noted. There were no significant changes in cardiac output, pulmonary arterial pressure, or left ventricular end-diastolic pressure. Significant reductions in left ventricular stroke work and ejection fraction were demonstrated. The amount of decrease in the ejection fraction was not related to the plasma pirmenol level achieved or to the baseline level of ventricular function. These findings suggest a negative inotropic effect of acute infusions of pirmenol and suggest caution should be used in its administration to patients with compromised left ventricular performance.

Adult↗
PubMed1987

Validation of in vivo two-dimensional echocardiographic dimension measurements using myocardial mass estimates in dogs.

The accuracy of in vivo measurements of left ventricular wall thickness and chamber size by means of two-dimensional echocardiography was investigated by comparing left ventricular mass estimates obtained at end diastole in 15 closed-chest dogs with a wide range of left ventricular weights. The systolic and diastolic echocardiographic mass estimates were compared with the actual weights of the freshly excised, stripped left ventricles immediately following death. The mean +/- SD of the weighed mass of the excised ventricles was 104 +/- 25 gm. The mean predicted left ventricular mass with the use of the cylinder-ellipse geometric model and gross anatomic sections corresponding to the echocardiographic imaging planes was 106 +/- 26 gm (r = 0.97 compared to the actual weight). The mean echocardiographic estimate of left ventricular mass at end diastolic was 107 +/- 24 gm (r = 0.98 compared to the weight) and 105 +/- 26 gm at end systole (r = 0.95 compared to the weight). The correlation between the echocardiographic mass estimate at end diastole and the echo mass estimate at end systole was 0.95. Regression analysis failed to demonstrate a significant over- or underestimation of the actual weight by the calculated mass with the use of either the gross anatomic or the in vivo echocardiographic dimension measurements.

Animals↗
PubMed1985

Prognostic value of a coronary artery jeopardy score.

The prognostic value of a coronary artery jeopardy score was evaluated in 462 consecutive nonsurgically treated patients with significant coronary artery disease, but without significant left main coronary stenosis. The jeopardy score is a simple method for estimating the amount of myocardium at risk on the basis of the particular location of coronary artery stenoses. In patients with a previous myocardial infarction, higher jeopardy scores were associated with a lower left ventricular ejection fraction. When the jeopardy score and the number of diseased vessels were considered individually, each descriptor effectively stratified prognosis. Five year survival was 97% in patients with a jeopardy score of 2 and 95, 85, 78, 75 and 56%, respectively, for patients with a jeopardy score of 4, 6, 8, 10 and 12. In multivariable analysis when only jeopardy score and number of diseased vessels were considered, the jeopardy score contained all of the prognostic information. Thus, the number of diseased vessels added no prognostic information to the jeopardy score. The left ventricular ejection fraction was more closely related to prognosis than was the jeopardy score. When other anatomic factors were examined, the degree of stenosis of each vessel, particularly the left anterior descending coronary artery, was found to add prognostic information to the jeopardy score. Thus, the jeopardy score is a simple method for describing the coronary anatomy. It provides more prognostic information than the number of diseased coronary arteries, but it can be improved by including the degree of stenosis of each vessel and giving additional weight to disease of the left anterior descending coronary artery.(ABSTRACT TRUNCATED AT 250 WORDS)

Coronary Angiography↗
PubMed1983

Serial thallium-201 imaging at rest in patients with unstable and stable angina pectoris: relationship of myocardial perfusion at rest to presenting clinical syndrome.

In order to determine whether there are differences in myocardial perfusion at rest among patients with various unstable and stable angina syndromes, serial thallium-201 imaging was performed at rest in 19 patients presenting with rapidly worsening exertional angina (unstable angina, group A), 12 patients with rest angina alone without exertional symptoms (unstable angina, group B), and 34 patients with chronic stable angina. No patient had an episode of angina within 4 hours of study. Nineteen of 19 (100%) patients in group A demonstrated transient defects compared to only 3 of 12 (25%) patients in group B (p less than 0.0001) and 4 of 34 (12%) stable angina patients (p less than 0.0001). The majority of zones demonstrating transient defects in group A were associated with hypokinesis of the corresponding left ventriculogram segment without associated ECG evidence of previous infarction. There were no significant differences in the frequency of persistent thallium defects, severity of angiographic coronary artery disease, or frequency of regional wall motion abnormalities of myocardial segments supplied by stenotic coronary arteries among the three groups of patients. Transient defects have been shown to reflect reduction in regional coronary blood flow to viable myocardium. Therefore, we conclude that regional resting hypoperfusion of viable myocardium is far more common in patients with exertional unstable angina symptoms than in patients with rest angina alone or chronic stable angina.

Angina Pectoris↗
PubMed1983

Evaluation of a QRS scoring system for estimating myocardial infarct size. III. Correlation with quantitative anatomic findings for inferior infarcts.

This study evaluated by quantitative autopsy correlation a previously developed scoring system for estimating the size of myocardial infarcts based on the QRS complex of the electrocardiogram. This system was tested using electrocardiograms from patients with infarcts shown by autopsy to predominate in the inferior third of the left ventricle. The study was limited to patients whose electrocardiogram did not indicate left or right ventricular hypertrophy, left or right bundle branch block, or left anterior or posterior fascicular block. Thirty-one patients from 6 medical centers met these criteria. In the electrocardiogram of 28 of the 31 patients (90%), lead a VF exhibited a Q wave of at least 30 ms. The correlation coefficient between the total QRS score and the percent infarction of the left ventricle was 0.74. In patients without confounding factors in the electrocardiogram and with single infarcts, the electrocardiogram provides a marker for infarcts in the inferior third of the left ventricle and a quantitative QRS scoring system provides an estimate of infarct size.

Aged↗
PubMed1983

The natural history and recommended management of patients with traumatic coronary artery fistulas.

Traumatic coronary artery fistulas are reported less often than other complications resulting from both penetrating and blunt trauma to the heart. We describe a 50-year-old man in whom the natural history of a traumatic coronary fistula is well documented. This patient, who was referred for evaluation and treatment of complications of a traumatic coronary artery fistula resulting from a shrapnel injury 31 years before admission to the hospital, had five cardiac catheterizations prior to undergoing definitive surgical repair. During this period, he progressed from being totally asymptomatic to having disabling angina and congestive heart failure. These symptoms developed even though the patient's left-to-right shunt remained constant; moreover, the symptoms appeared to develop secondary to a "steal" of myocardial blood flow from the uninvolved coronary arterial bed through tortuous collaterals. Based on this experience and supported by published reports of 25 other patients, we recommend that nearly all patients with traumatic coronary artery fistulas be considered as candidates for elective surgical repair in order to prevent the eventual development of serious and possibly life-threatening complications. Operative repair can be accomplished safely with excellent long-term results.

Angina Pectoris↗
PubMed1983

Functional improvement of jeopardized myocardium following intracoronary streptokinase infusion in acute myocardial infarction.

The effect of reperfusion on regional left ventricular performance following acute myocardial infarction in man was determined. Intracoronary streptokinase was administered in 24 patients within 6 h of the onset of symptoms. 15 patients (62%) were successfully recanalized during the initial study. Mean percent radial shortening (%RS) in both the jeopardized and compensatory regions were determined using 23 radii from the centroid of diastolic and systolic angiographic silhouettes. Sequential measurements were obtained during repeat cardiac catheterization studies at 24 h in 19 patients and before discharge from the hospital (16 +/- 11 d) in 15 patients. At the time of the predischarge study, each acutely reperfused patient showed improvement in %RS in the jeopardized region (P = 0.01) with 56% returning to the normal range. Despite the uniform improvement in the contractile function of the jeopardized region in each reperfused patient, the global ejection fraction showed no improvement or a decrease at the time of the chronic study in 44%. This was due to a decrease in the compensatory wall motion in the uninvolved segments between the acute and chronic study in each case. Neither the %RS nor the ejection fraction changed significantly at the time of the chronic study in the patients who could not be acutely recanalized. These data indicate (a) significant salvage of jeopardized myocardium associated with recovery of contractile function in patients reperfused during the first 6 h of chest pain following acute myocardial infarction; (b) no improvement in regional or global left ventricular performance in patients who could not be reperfused acutely; and (c) the ejection fraction is strongly influenced by changes in the compensatory wall motion of the uninvolved segments and does not accurately reflect changes in the contractile function of the jeopardized myocardium.

Adult↗
PubMed1983

Serial changes in left ventricular ejection fraction in the early hours after aortocoronary bypass grafting.

To determine the course of left ventricular ejection fraction (LVEF) in the early hours after aortocoronary bypass grafting, 24 patients underwent serial gated bloodpool scanning. Twenty-two had received propranolol until the day of surgery. ECGs showed no evidence of perioperative infarction. Preoperatively, the mean (+/- SD) LVEF was 0.56 +/- 0.13; after bypass, it was 0.38 +/- 0.11 at 4 hours, 0.42 +/- 0.12 at 5 hours, 0.43 +/- 0.11 at 6 hours, 0.48 +/- 0.13 at 7 hours, 0.52 +/- 0.15 at 8 hours, and 0.54 +/- 0.15 at 10 to 14 days. The LVEFs at 4, 5, and 6 hours postoperatively were significantly lower than preoperatively (p less than 0.05). Postoperative mean heart rate was higher at all times; mean temperature was depressed at 4 and 5 hours and elevated at 7 and 8 hours; and mean arterial blood pressure was depressed at 7 hours, 8 hours, and 10 to 14 days (p less than 0.05). The degree of the early postoperative LVEF depression correlated with the daily preoperative propranolol dose (p less than 0.05) and was unrelated to bypass time, aortic cross-clamp time, or changes in temperature, heart rate, and blood pressure. The LVEF at 10 to 14 days postoperatively was not significantly different from the preoperative value. The LVEF is depressed in the early hours after aortocoronary bypass grafting and approaches the preoperative value with time. The magnitude of the early depression appears to be related to the preoperative propranolol dose, but does not significantly correlate with factors related to surgical technique.

Adult↗
PubMed1983

Adverse effects of nifedipine therapy on hypertrophic obstructive cardiomyopathy.

A 62-year-old man with obstructive hypertrophic cardiomyopathy was given sublingual nifedipine, 10 mg, during invasive hemodynamic monitoring. After 15 minutes, his left ventricular outflow gradient increased from 22 to 80 mm Hg while arterial pressure fell from 152/70 to 122/64 mm Hg. Left ventricular end-diastolic pressure increased from 15 to 22 mm Hg. These adverse hemodynamic responses may have been a result of vasodilation of the peripheral circulation induced by nifedipine. Thus, some patients with hypertrophic obstructive cardiomyopathy may develop serious hemodynamic compromise when treated with nifedipine.

Atrial Fibrillation↗