Images in clinical medicine. Massive arteriovenous malformation.
Explore the source record for details and available documents.
Aged↗
Biomedical subjects
B W Usher
Publications and source records attributed to B W Usher.
Treatment of coronary artery disease in hemodialysis patients: PTCA vs. stent.
This retrospective study examined the utilization of coronary stent placement versus PTCA in hemodialysis patients with obstructive coronary disease. Prior studies have demonstrated suboptimal results with PTCA owing primarily to high rates of restenosis. We identified 19 hemodialysis patients who received a percutaneous coronary intervention who were matched with individuals without renal failure undergoing same vessel revascularization. Our study found that 71% of hemodialysis patients receiving PTCA had a recurrent cardiac event defined by subsequent angina, myocardial infarction, or cardiac death. At follow-up, 30% of patients who received stent placement had recurrent cardiac events. Intracoronary stent placement is both safe and feasible and produces more favorable clinical outcomes in the management of coronary disease in hemodialysis patients.
Adult↗
Recent advances in dobutamine stress echocardiography.
Dobutamine stress echocardiography (DSE) is a reliable cardiac risk stratifier that has widespread applicability because of its clinical accuracy and cost effectiveness. Dobutamine has positive inotropic and chronotropic effects and is commonly used in patients who cannot exercise or achieve an adequate heart rate response with exercise. Recently available long-term results from several independent clinical trials, combined with enhancements in image quality, have improved the ability to detect significant coronary artery disease and determine myocardial viability. Dobutamine stress echocardiography has an excellent safety profile with clinical results superior to regular exercise electrocardiography and comparable with exercise echocardiography and radionucleotide perfusion stress imaging. Low-dose dobutamine response can accurately predict dysfunctional yet viable myocardial regions that may improve with revascularization. Clinical studies are now available refining the common use of DSE preoperatively in female patients with valvular disease, as well as in the emergency department. Dobutamine stress echocardiography does have some limitations in discriminating particular regions of ischemia when multiple ventricular segments are involved and when the imaging is suboptimal. It can be applied using minimal additional resources in an otherwise functioning echocardiography laboratory and, with appropriate training, can result in clinical results comparable with those of large-scale multicenter trials. Ongoing improvements in technology and the development of new reagents such as myocardial contrast agents hold promise for further advancement in the near future.
Cardiotonic Agents↗
Balloon aortic valvuloplasty: five year experience at MUSC.
Explore the source record for details and available documents.
Adult↗
The utility of intravascular ultrasound in evaluating pulmonary artery anastomosis in a lung transplantation swine model.
Explore the source record for details and available documents.
Anastomosis, Surgical↗
Left ventricular pseudoaneurysm after myocardial infarction.
Explore the source record for details and available documents.
Aneurysm, False↗
An unusual cause of the high-output state.
Explore the source record for details and available documents.
Aged↗
Steroid-induced osteonecrosis of the humeral head.
Steroid-induced osteonecrosis is a disease of modern medicine. Prevention remains the hallmark of management; however, as long as there are medical conditions requiring steroid therapy, osteonecrosis will remain a problem. An understanding of the pathophysiology, in addition to the clinical and radiographic manifestations of this disease process, will aid the physician in the unique challenge of diagnosing and treating osteonecrosis of the humeral head.
Diagnostic Imaging↗
Effect of catheter positioning on the variability of measured gradient in aortic stenosis.
The purpose of this study was to quantify the variation in measured aortic valve gradient and calculated aortic valve area when different techniques of cardiac catheterization were utilized. Hemodynamic assessment of aortic stenosis severity requires an accurately determined pressure gradient. In aortic stenosis, the presence of intraventricular pressure gradients and downstream pressure recovery within the aorta means that a range of aortic valve gradients could be measured in a given patient depending upon catheter position and measurement technique. To quantify the degree of variation in measured gradient and calculated aortic valve area, we generated transvalvular gradients by nine different techniques in 15 patients (11 men, 4 women; 29-86 years old). Patients were divided into those with severe aortic stenosis (aortic valve area < or = 0.6 cm2, n = 6) and those with moderately severe aortic stenosis (aortic valve area 0.61-0.90 cm2, n = 9). Considerable variation in measured gradient and calculated aortic valve area was observed. The maximum variation in gradient was similar in severe and moderately severe aortic stenosis groups (33 mm Hg. vs. 32 mm Hg., p = NS). However, the variation in gradient as a percent of maximum gradient was greater (P < 0.05) in the moderately severe aortic stenosis group. The maximum variation in calculated aortic valve area was 0.1 cm2 in the severe group and 0.3 cm2 in the moderately severe group (P < 0.01). An intraventricular gradient, present in 13 of 15 (87%) patients, was partially responsible for the variation in pressure gradient measurement and calculated aortic valve area.(ABSTRACT TRUNCATED AT 250 WORDS)
Adult↗
Cardiac valvular disease and stroke.
Cerebrovascular accidents secondary to thromboembolic complications of native valve disease as well as prosthetic valves continue to be a major medical problem. The role of anticoagulation in various abnormalities is discussed in this article.
Brain↗
Cardiovascular status of panic disorder patients with and without prominent cardiac symptoms.
The extent of the cardiovascular evaluation of panic disorder patients with cardiac symptoms remains a dilemma for the clinician. The authors conducted a pilot study to assess the cardiac status of 20 panic disorder patients, 10 of whom had prominent cardiac symptoms and 10 of whom did not. No differences in the cardiac abnormalities were found between the groups. These findings suggest that panic disorder patients with cardiac symptoms are not more likely to have cardiac disease than those without prominent cardiac symptoms. The practical implications of these findings are discussed.
Adult↗
Mitral valve replacement with and without chordal preservation in patients with chronic mitral regurgitation. Mechanisms for differences in postoperative ejection performance.
BACKGROUND: Standard mitral valve replacement (MVR) in patients with chronic mitral regurgitation consistently results in a decrease in postoperative left ventricular (LV) ejection performance. This fall in ejection performance has been attributed, at least in part, to unfavorable loading conditions imposed by the elimination of the low-impedance pathway for LV emptying into the left atrium. In contrast to standard MVR in which the chordae tendineae are severed, however, MVR with chordal preservation (MVR-CP) does not usually decrease LV ejection performance despite similar removal of the low-impedance pathway. The purpose of the present study was to define the mechanisms responsible for this discordance in postoperative ejection performance between MVR with and without chordal preservation. METHODS AND RESULTS: Echocardiography and sphygmomanometer blood pressures were obtained in 15 patients with pure chronic mitral regurgitation before and 7-10 days after mitral valve surgery. These measurements were used to calculate ventricular volume, wall stress, and ejection fraction. Seven patients underwent MVR with chordal transection (MVR-CT), and eight patients underwent MVR-CP. MVR-CT resulted in no postoperative change in LV end-diastolic volume, a significant increase in LV end-systolic volume, a significant increase in end-systolic stress, from 89 +/- 9 to 111 +/- 12 g/cm2 (p < 0.05), and a significant decrease in ejection fraction, from 0.60 +/- 0.02 to 36 +/- 0.02 (p < 0.05). In contrast, patients who underwent MVR-CP had a significant decrease in LV end-diastolic and end-systolic volumes. End-systolic wall stress actually fell from 95 +/- 6 to 66 +/- 6 g/cm2 (p < 0.05), and ejection fraction was unchanged (0.63 +/- 0.01 before and 0.61 +/- 0.02 after mitral valve surgery) instead of reduced. CONCLUSIONS: MVR-CT resulted in a decrease in ejection performance caused in part by an increase in end-systolic stress, which in turn increased end-systolic volume. Conversely, MVR-CP resulted in a smaller LV size, allowing a reduced end-systolic stress and preservation of ejection performance despite closure of the low-impedance left atrial ejection pathway.
Chordae Tendineae↗
Valve surgery: indications and long-term results.
The decision to perform valve surgery requires knowledge of the natural history of valvular heart disease and of the results of surgical therapy. Recent reports have shed light on these important factors. Long-term results of valvular surgery are multifactorial, and data relating to age, type of prosthetic valve, and anticoagulation are presented.
Age Factors↗
The fractional shortening-velocity ratio: validation of a new echocardiographic Doppler method for identifying patients with significant aortic stenosis.
Previous studies have shown that Doppler echocardiographic methods based on the continuity equation can accurately determine aortic valve area in patients with clinically significant aortic stenosis; nonetheless, methods based on the continuity equation are time-consuming and may not be technically possible in all subsets of patients. The purpose of this study was to develop and prospectively evaluate a simpler new noninvasive method for determining aortic valve area. With this new method, aortic valve area is obtained by dividing the percent fractional anteroposterior shortening at the midventricular level by 4V2, where V is the peak instantaneous Doppler-derived flow velocity across the aortic valve. In the first part of the study, the fractional shortening-velocity ratio was used to examine a group of 25 patients evaluated retrospectively. There was a highly significant linear relation between the fractional shortening-velocity ratio (FSVR) and the aortic valve area (AVA) determined by the Gorlin formula at cardiac catheterization: FSVR = 1.1(AVA) - 0.1 (r = 0.88; significance of slope p less than 0.001). Furthermore, a fractional shortening-velocity ratio less than 1.1 reliably identified all patients with clinically significant aortic stenosis (aortic valve area less than 1 cm2), whereas a fractional shortening-velocity ratio less than 0.8 reliably identified all patients with critical aortic stenosis (aortic valve area less than 0.7 cm2). This new method was then validated by prospectively applying the fractional shortening-velocity ratio to a group of 44 patients from two separate institutions.(ABSTRACT TRUNCATED AT 250 WORDS)
Aortic Valve↗
Left ventricular dysfunction in symptomatic mitral valve prolapse.
Idiopathic MVP is characterized by a late systolic click or murmur from myxomatous mitral valvular dysfunction. It may be complicated by atypical chest pain, ventricular arrhythmias, and ECG changes that can mimic the symptoms of coronary artery disease. We prospectively performed radionuclide cineangiograms before and after stress tests in MVP patients with chest pain compared with asymptomatic MVP patients and symptomatic normal control patients. In ten patients with MVP, chest pain, and normal coronary anatomy, the LVEF remained essentially unchanged (increase of -0.5 +/- 4 percent) after exercise. In ten patients with MVP and no chest pain and in nine with normal cardiovascular system and chest pain, the exercise LVEF increased by 11.5 +/- 2 percent (p less than 0.05) and 17.4 +/- 3 percent (p less than 0.005), respectively. The resting LVEF was significantly lower (p less than 0.02) in the symptomatic MVP patients (59 +/- 3 percent) than in the asymptomatic MVP (76 +/- 5 percent) or symptomatic normal patient control subjects (70 +/- 3 percent). Patients with MVP and chest pain had a lower resting LVEF and an abnormal left ventricular functional response to exercise compared with asymptomatic MVP patients or symptomatic normal subjects. Therefore, exercise radionuclide ventriculography may not adequately differentiate between chest pain due to MVP or coronary artery disease.
Cineangiography↗
Intravenous streptokinase therapy for acute myocardial infarction in a community hospital: effect on ventricular function and mortality.
Streptokinase can dramatically impact upon management of myocardial infarctions in community hospitals. When given by experienced personnel during the first six hours after onset of symptoms, streptokinase is associated with a high patency rate, improved left ventricular function, and reduced mortality. Careful screening of patients results in a low complication rate with infrequent serious bleeding. Streptokinase should be utilized in those hospitals without cardiac catheterization facilities, but in light of the relatively high incidence of recurrent pain (15.8%), transfer of stable patients to a facility with a catheterization laboratory should be carried out within 24 to 72 hours. As approximately 60% of patients will require PTCA, CABG, or both, diagnostic cardiac catheterization should be considered in all patients unless there are other mitigating factors.
Acute Disease↗
Incidence of acute myocardial infarction in patients with exercise-induced silent myocardial ischemia.
Fifty-five patients with angiographically proved coronary artery disease (CAD) underwent Bruce protocol exercise stress testing with thallium-201 imaging. Twenty-seven patients (group I) showed myocardial hypoperfusion without angina pectoris during stress, which normalized at rest, and 28 patients (group II) had a similar pattern of reversible myocardial hypoperfusion but also had angina during stress. Patients were followed for at least 30 months. Six patients in group I had an acute myocardial infarction (AMI), 3 of whom died, and only 1 patient in group II had an AMI (p = 0.05), and did not die. Silent myocardial ischemia uncovered during exercise stress thallium testing may predispose to subsequent AMI. The presence of silent myocardial ischemia identified in this manner is of prognostic value, independent of angiographic variables such as extent of CAD and left ventricular ejection fraction.
Angina Pectoris↗
Predictors of outcome for aortic valve replacement in patients with aortic regurgitation and left ventricular dysfunction: a change in the measuring stick.
Although left ventricular function is generally regarded as a key determinant of prognosis in aortic regurgitation, predictors of outcome of aortic valve replacement based on this factor have recently been questioned. This study was performed to examine the role of indexes of left ventricular function in predicting the outcome of surgery in patients with aortic regurgitation and left ventricular dysfunction. Fourteen patients with aortic regurgitation with a preoperative ejection fraction of less than 0.55 (average 0.45 +/- 0.02) who underwent aortic valve replacement were studied. The patients had 82 (58%) of a possible 140 predictors of negative outcome preoperatively, but 12 of the 14 patients had a decrease in symptoms and an increase in ejection fraction into the normal range after operation (average postoperative ejection fraction 0.59 +/- 0.04). Although improvement occurred despite the presence of many negative predictors of outcome, there was a significant correlation between postoperative ejection fraction and eight of the tested preoperative predictors. Preoperative end-systolic dimension correlated best (r = -0.91) with postoperative ejection fraction. An end-systolic dimension of 60 mm correlated with a postoperative ejection fraction of 0.55. The results indicate that preoperative ventricular function is still an important determinant of outcome of aortic valve replacement for aortic regurgitation. However, current medical and surgical techniques permit a better prognosis in the presence of reduced ventricular function than was previously considered possible.
Aortic Valve Insufficiency↗