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Biomedical subjects

H S Cabin

Publications and source records attributed to H S Cabin.

At least 19 recordsLinked to original sources
PubMed1992

Frequency of long-term lower limb ischemia associated with intraaortic balloon pump use.

Lower limb ischemia is a frequent complication of intraaortic balloon pump (IABP) use. The incidence and risk factors for acute ischemia have been well-defined, but little is known about long-term ischemic complications. This prospective study evaluated the incidence, nature, progression and predisposing factors for long-term lower limb ischemia in 151 patients who were previously treated with the IABP. These persons were interviewed and their lower extremities examined 12 to 20 months after undergoing IABP counterpulsation. Limb ischemia, characterized primarily by ipsilateral discomfort and diminished pulses, occurred in 18% of those evaluated. Evidence of ischemia worsened over time in 14%. Logistic regression analysis, which was based on variables found to be significant in bivariate analysis, revealed that the occurrence of limb ischemia acutely, cardiogenic shock as an indication for IABP insertion, and smoking (at the time of hospitalization or having quit < 10 years previously) were risk factors for long-term lower limb ischemia. The adjusted odds ratio for acute limb ischemia was 8.89 (95% confidence interval 2.80 to 28.21), for cardiogenic shock 3.59 (95% confidence interval 1.01 to 12.75), and for smoking 2.87 (95% confidence interval 1.10 to 7.46). Increasing numbers of patients are undergoing IABP counterpulsation and a greater proportion of these are surviving their acute event and resuming active lives. It is essential to recognize that detrimental consequences of this device can persist long after hospitalization.

Adult↗
PubMed1992

Equine arch vessel anomaly associated with coarctation of the aorta.

Angiography in a 30-year-old man revealed the unique combination of aortic coarctation and an unusual arch anomaly. Proximal to the coarctation, a single arch vessel trifurcated into the brachiocephalic, left common carotid and left subclavian arteries. This anomalous arch vessel is a normal equine variant.

Abnormalities, Multiple↗
PubMed1992

Right ventricular infarction.

Right ventricular myocardial infarction, long unrecognized because of a lack of diagnostic methods and unsupported beliefs regarding the dispensability of the right ventricle, may now be diagnosed using well-accepted criteria. Right ventricular infarction is clearly associated with anterior left ventricular infarction as well as inferior infarction. It may occur in 30% to 40% of patients with inferior infarction, although a much smaller percentage experience hemodynamic instability on the basis of right ventricular infarction. Pathophysiologically, right ventricular systolic and diastolic dysfunction are exacerbated by pericardial restraint and concomitant left ventricular dysfunction, accounting for the characteristic findings of cardiogenic shock and marked preload dependence in many patients. Right ventricular infarction may be suspected on the grounds of clinical presentation, physical examination, and enzymatic findings, and is confirmed using well-defined electrocardiographic, radionuclide, echocardiographic, and hemodynamic criteria. Once diagnosed, right ventricular infarction requires specific hemodynamic and pharmacologic management, including the judicious use of volume expansion and inotropic support. Several forms of mechanical and surgical intervention are of therapeutic value in treating hemodynamic disturbances and recognized complications. With appropriate management, the prognosis for patients with right ventricular infarction is generally favorable.

Diagnosis, Differential↗
PubMed1991

Validation of continuous radionuclide left ventricular functioning monitoring in detecting silent myocardial ischemia during balloon angioplasty of the left anterior descending coronary artery.

Silent myocardial ischemia has been inferred from transient ST-segment depression during continuous electrocardiographic monitoring. Recently, continuous ambulatory monitoring of left ventricular (LV) function using a radionuclide technique (VEST) has demonstrated episodes of significant silent LV dysfunction in the absence of electrocardiographic changes. To validate the demonstration of silent LV dysfunction with this technique, 12 men were studied during percutaneous transluminal coronary angioplasty. A total of 18 left anterior descending coronary artery balloon inflations were performed. Balloon inflations at 8 +/- 2 atm (4 to 10 atm) lasted 70 +/- 16 seconds. Seventeen of 18 inflations were associated with a decrease in LV ejection fraction greater than 0.10. Mean LV ejection fraction decreased from 0.53 +/- 0.08 to 0.28 +/- 0.11 (p less than 0.0001). In contrast, there was pain in only 10 inflations and ST-segment changes in 7. LV dysfunction was associated with a minimal increase in end-diastolic volume (4 +/- 3%, p less than 0.003), and a major increase in relative end-systolic volume (69 +/- 43%, p less than 0.001). These data suggest that continuous monitoring of LV function with the VEST can sensitively detect silent ischemic decreases in LV function occurring during angioplasty, and provide further validation of the use of this technique for detecting silent myocardial ischemia.

Aged↗
PubMed1991

Clinical experience with the Palmaz-Schatz coronary stent. Initial results of a multicenter study.

Stenting of native coronary arteries with a balloon-expandable stent was attempted in 226 patients after elective angioplasty. Delivery of the device was successful in 213 (94%) of the patients. Of these, 39 received aspirin and dipyridamole only (group 1) and 174 received aspirin, dipyridamole, and warfarin for 1-3 months (group 2). There was no abrupt closure (less than or equal to 1 day) or perioperative death in either group. In-hospital or perioperative complications in group 1 compared with group 2 were as follows: subacute closure (1-14 days), seven (18%) patients versus one (0.6%) patient, respectively, p less than 0.0001; myocardial infarction, five (13%) patients versus one (0.6%) patient, respectively; condition requiring urgent bypass surgery, one (2.5%) patient versus no patients, respectively. Thus, the incidence of major complications such as death, myocardial infarction, or a condition requiring urgent bypass surgery was 15% in group 1 and 0.6% in group 2. Clinical follow-up revealed that 92% of the patients were asymptomatic at 3 months after stenting compared with 6% before stenting (p less than 0.0001). Of the 13 patients who were symptomatic, nine underwent cardiac catheterization and, ultimately, successful elective coronary angioplasty or bypass surgery. We conclude that a high delivery success rate can be expected with this device and that clinical thrombosis is less frequent in anticoagulated patients than in nonanticoagulated patients. Furthermore, in this selected patient population, coronary stenting results in a low incidence of in-hospital and perioperative complications. Clinical success, defined by absence of symptoms, appears to be sustained at 3 months.

Angioplasty, Balloon, Coronary↗
PubMed1991

Pulmonary embolism presenting as exercise-induced hypotension.

A 68-year-old man with remote history of previous myocardial infarction presented with a four-week history of intermittent dyspnea. After developing hypotension during an exercise tolerance test, he underwent cardiac catheterization, revealing significant pulmonary hypertension and two-vessel coronary artery disease. Pulmonary angiography confirmed the presence of pulmonary emboli which partially resolved after thrombolytic therapy. Subsequent treadmill testing confirmed the absence of exercise-induced hypotension two months following treatment. This case underscores the importance of considering pulmonary embolism as a potential cause of exercise-induced hypotension, since it can be successfully treated with thrombolytic agents weeks after the initial onset of symptoms.

Aged↗
PubMed1990

Risk for systemic embolization of atrial fibrillation without mitral stenosis.

The risk for systemic embolization was studied in 272 patients without mitral stenosis or prosthetic valves who were referred to the echocardiography laboratory with atrial fibrillation (AF). During a mean follow-up period of 33 months (range less than 1 to 83), 27 (10%) patients had a systemic embolic event, which was cerebral in 23 patients (85%) and peripheral in 4 (15%). In the analysis of individual variables, the risk of embolization was increased by female sex, underlying heart disease and left atrial size greater than or equal to 4.0 cm, but not by age, hypertension or type of AF (paroxysmal vs chronic). In multivariable analysis, left atrial size greater than or equal to 4.0 cm was the single strongest predictor of increased risk for embolization (p less than 0.001), but female sex (p = 0.014) and underlying heart disease (p = 0.027) also contributed. When each of these 3 factors was assigned 1 point in a risk score, embolic events were found to occur in none (0%) of 24 patients with a risk score of 0, in 2 (3%) of 83 patients with a risk score of 1, in 13 (11%) of 118 patients with a risk score of 2 and in 12 (26%) of 47 patients with a risk score of 3. The score allows patients with AF and without mitral stenosis to be stratified into high-, medium- and low-risk groups for systemic embolization. Such information could be useful in decision making for anticoagulation in patients with AF.

Aged↗
PubMed1989

Predictors of success in percutaneous transluminal coronary angioplasty of chronic total occlusions.

Earlier studies have indicated that percutaneous transluminal coronary angioplasty (PTCA) of chronic total occlusions has a low success rate. To determine success rate and assess clinical and angiographic variables associated with success and complications, 57 total occlusions in 56 patients undergoing PTCA were analyzed. The clinical duration of occlusion was 51 +/- 86 days. Success (less than 50% residual stenosis) was achieved at 40 of 57 (70%) dilatation sites. Of these 57 total occlusions, 5 were attempted within 24 hours of acute myocardial infarction, 35 between 1 day and 8 weeks of clinical occlusion, 13 greater than 8 weeks and 4 were of unknown duration. Success rates were 4 of 5, 25 of 35, 9 of 13 and 2 of 4, respectively, in each group (difference not significant, comparison of all time groups). Of the 9 narrowings with a successful PTCA for an occlusion greater than 8 weeks, the mean duration of occlusion was 93 +/- 41 days (range 60 to 180). None of the attempted dilatations of occlusions with a clinical duration of greater than 180 days (n = 3) was successful. None of the clinical or angiographic variables (including tortuosity, length of occlusion gap, distance of the occlusion from the vessel origin, thrombus, lesion calcium, collaterals, prior myocardial infarction, vessel dilated or diffuse disease) impacted on success rate (difference not significant for all). No patient died, had a Q-wave infarction, required emergency coronary artery bypass grafting or underwent repeat PTCA within 7 days of the procedure. Non-Q-wave infarction occurred in 2 of 56 patients (4%).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1989

Pulmonary and pleural complications of cardiac disease.

Disorders of the heart frequently cause pulmonary dysfunction because of the close structural and functional association of the heart and lungs. The pulmonary vasculature is very commonly affected by cardiac pathology. The pulmonary vasculature is normally a low-pressure, low-resistance circuit with high compliance and tremendous vascular reserve. Although resting vascular tone is low, there are many identified mediators of pulmonary arterial tone that may help mediate pulmonary blood flow. Alveolar hypoxia is clearly a stimulus for increasing pulmonary vascular resistance although factors that mediate the response to hypoxia are not fully understood. Patients with left-to-right shunting due to congenital heart disease because of elevations in pulmonary artery flow and pressure tend to develop progressive anatomic changes in the pulmonary vasculature. This leads to an increase in pulmonary vascular resistance, irreversible pulmonary hypertension, right heart failure, reversal of shunt flow, and Eisenmenger's syndrome. The degree of anatomic vascular damage due to left-to-right shunting can be graded histologically. Lesser grades of damage are reversible with corrective surgery, whereas more severe grades show no improvement or progression with operation. Chronic left-sided congestive heart failure seen in rheumatic mitral stenosis can cause secondary changes in the pulmonary vasculature. Pulmonary hypertension and increased pulmonary vascular resistance can increase reflexly and form a "second stenosis" that further limits cardiac output. Unlike congenital heart disease, severe grades of pulmonary arterial damage are not seen in left heart failure from mitral stenosis or other causes, and consequently with surgical correction pulmonary hypertension reverses. Pulmonary function testing is adversely affected by congestive heart failure. Both restrictive (stiff lungs) and obstructive (cardiac asthma) defects are observed in congestive heart failure. DLCO is abnormally decreased. With treatment of heart failure these defects reverse. Both elevated systemic and pulmonary venous pressures affect fluid filtration in the pleural space and cause pleural fluid accumulation. The fluid is transudative with low protein, low lactate dehydrogenase, and low cell counts. Transudative effusions from heart failure resolve with treatment. With large effusions and cardiomegaly, pulmonary dysfunction results because of atelectasis from compression and space-occupying effects of the heart and pleural fluid. Following myocardial infarction, cardiac surgery, or other cardiac trauma, the postcardiac injury syndrome can result. The syndrome is characterized by exudative pleural and pericardial effusions along with pulmonary infiltrates, fever, chest pain, leukocytosis, and an elevated ESR. The syndrome must be diagnosed by exclusion of bacterial pneumonia, pulmonary emboli, and congestive heart failure. Treatment is with nonsteroidal anti-inflammatory agents or systemic co

Cardiovascular Agents↗
PubMed1988

Relation of peak creatine kinase levels during acute myocardial infarction to presence or absence of previous manifestations of myocardial ischemia (angina pectoris or healed myocardial infarction).

The hypothesis that acute myocardial infarction (MI) is more extensive in patients without previous angina or healed MI was evaluated in 177 patients with documented recent acute MI. Ninety-nine patients (56%) had no previous angina or healed MI (negative history group), and the remaining 78 patients (44%) had a previous history of angina or healed MI (positive history group). The mean peak creatine kinase (CK) level in the negative history group was 784 compared with 419 IU in the positive history group (p less than 0.0001). The mean peak CK-MB level in the negative history group was 128 compared with 76 IU in the positive history group (p less than 0.001). The mean peak CK-MB level was higher in the negative history group after controlling for age, streptokinase administration, previous coronary artery bypass grafting or treatment with beta-blocking agents. Despite the high frequency of healed MI in the positive history group (73%), the rates of in-hospital complications were similar for the 2 groups. Patients with acute MI without previous angina or healed MI have substantially higher peak CK and CK-MB levels; this implies a larger MI than in patients with previous angina or healed MI.

Aged↗
PubMed1988

Dynamics of early and late left ventricular filling determined by Doppler two-dimensional echocardiography during percutaneous transluminal coronary angioplasty.

To study the influence of ischemia on both early and late left ventricular filling, Doppler 2-dimensional echocardiography was used to measure filling parameters during percutaneous transluminal coronary angioplasty (PTCA) in 26 patients. Doppler recordings were taken immediately before balloon inflation and continuously during balloon inflation and deflation until 60 seconds into the recovery period. During PTCA of the left anterior descending artery (16 patients) there was a 35% decrease in early peak filling rate from 269 +/- 88 to 169 +/- 55 ml/s (p less than 0.0005) by 60 seconds of balloon inflation. In patients undergoing PTCA of the left circumflex (4 patients) or dominant right coronary artery (6 patients), the early peak filling rate decreased 15% from 325 +/- 126 to 284 +/- 137 ml/s (p less than 0.005). The decrease in early peak filling rate became evident at approximately 15 seconds after balloon inflation and fully recovered 20 seconds after balloon deflation. Rather than an expected increase in atrial stroke volume and a decrease in early to late filling ratio during coronary occlusion, there was a 28% decrease in atrial stroke volume during left anterior descending coronary artery PTCA and a 6% decrease during right coronary and circumflex PTCA. Because of the simultaneous decrease in both early and late ventricular filling, peak early to late filling ratio was only slightly altered during PTCA. There was an 83% increase in mean pulmonary artery wedge pressure during balloon inflation from 12 +/- 5 to 20 +/- 4 mm Hg. In 11 of these patients global systolic function was measured on subsequent inflations during PTCA using 2-dimensional echocardiography.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1988

Analgesic therapy in acute myocardial infarction.

Parenterally administered narcotic analgesics are a critically important part of therapy for the patient with acute myocardial ischemic syndromes. These agents are very effective and, when used with appropriate caution and monitoring, are also generally safe. They not only relieve the sensation of severe pain but also reduce the effective and physiologic reaction to pain and thus reduce patient anxiety. Because these agents all depress respiratory drive to some degree in the doses used for adequate analgesia, close attention to respiratory status is mandatory. In patients with underlying pulmonary disease or significant congestive heart failure, this monitoring should be even more intensive and include arterial blood gas measurements and preparations for possible narcotic antagonist administration and ventilatory assistance. With regard to the hemodynamic changes produced by these agents, several important points are worth noting. It must be remembered that the conclusions regarding hemodynamic effects of these agents are derived from studies involving patient groups that were generally hemodynamically stable, usually pain-free, and almost always at least several hours following acute presentation. Thus, the hemodynamic effects of these agents may be quite different in patients with active pain during a period of acute ischemia, or in patients that are hemodynamically unstable. Hemodynamic studies during these acute settings, however, are extremely difficult to perform because the patient's acute distress mandates rapid administration of an analgesic agent prior to the institution of invasive monitoring. With these cautions relating to data interpretation in mind, it is still possible to make certain recommendations regarding the use of analgesic therapy in acute MI.(ABSTRACT TRUNCATED AT 250 WORDS)

Analgesics↗
PubMed1988

Update on percutaneous transluminal coronary angioplasty.

Percutaneous transluminal coronary angioplasty was first performed in a human coronary artery in 1977. In this article, we review the possible mechanisms of angioplasty, current indications for angioplasty, and complications of angioplasty including acute closure and restenosis.

Angioplasty, Balloon↗
PubMed1988

The role of anticoagulation in acute myocardial infarction.

The rule of anticoagulation therapy in the setting of an acute myocardial infarction has been debated for decades. The role of such therapy in reducing mortality, preventing deep venous thrombosis and pulmonary emboli, and in reducing the frequency of left ventricular thrombus formation and subsequent systemic embolization is discussed.

Anticoagulants↗
PubMed1987

Discrimination of normal and atherosclerotic aorta by laser-induced fluorescence.

Precise targeting of laser energy to atherosclerotic plaque is crucial for the safe performance of laser angioplasty. The present study was designed to evaluate whether laser-induced fluorescence could distinguish atherosclerotic from normal aorta. Segments of human aorta obtained at necropsy were classified grossly and histologically as normal aorta (n = 7), thin yellow fatty plaque (n = 5), and thick white atheromatous plaque (n = 9), and analyzed by laser-induced fluorescence spectroscopy using a pulsed nitrogen laser. Fluorescence spectra were recorded over a wavelength range from 385 to 725 nm. Normal specimens had maximal fluorescence intensity at 514 nm. A prominent fluorescence peak at 448 nm was present in specimens characterized as white atheromatous plaque and at 538 nm in specimens characterized as yellow fatty plaque. The ratios of fluorescence intensity at 448 nm/514 nm and at 538 nm/514 nm correctly classified all specimens according to their gross and histologic type (p less than .001). Thus, a "smart" laser angioplasty catheter system might incorporate low-power laser radiation for arterial fluorescence spectroscopy to guide delivery of high-power laser radiation for plaque ablation.

Aorta↗
PubMed1987

Right ventricular myocardial infarction with anterior wall left ventricular infarction: an autopsy study.

Right ventricular myocardial infarction has been reported to occur exclusively in association with inferior left ventricular infarction. To determine the frequency of right ventricular myocardial infarction in association with anterior left ventricular myocardial infarction, all hearts with anterior myocardial infarction studied over a 3-year period were examined for evidence of right ventricular necrosis or scar. Of 97 hearts with anterior myocardial infarction, 13 (13%) had anterior right ventricular myocardial infarction. The right ventricular infarcts involved from 10% to 50% (mean 28%) of the circumference of the right ventricular free wall from base to apex. The associated left ventricular infarcts were all anteroseptal and large and involved from 36% to 67% (mean 50%) of the total area of the left ventricular free wall and septum. Nine of the 13 patients underwent equilibrium radionuclide angiography and six had demonstrable right ventricular regional and global dysfunction. Thus, right ventricular myocardial infarction does occur with anterior wall left ventricular infarction, and right ventricular dysfunction may be demonstrable by radionuclide angiography. Further investigation is needed to define the hemodynamic characteristics, clinical importance, and therapeutic implications of anterior right ventricular myocardial infarction.

Adult↗