Biomedical subjects
W D Keen
Publications and source records attributed to W D Keen.
Eustachian valve endocarditis: detection with multiplane transesophageal echocardiography.
Right-sided involvement is fairly common in infective endocarditis, but involvement of the eustachian valve is distinctly rare. We present the case of a 36-year-old intravenous drug user with staphylococcal bacteremia and septic pulmonary emboli. Transthoracic echocardiography was normal, but transesophageal echocardiography revealed a large eustachian valve vegetation. This case illustrates the utility of multiplane transesophageal echocardiography in the evaluation of eustachian valve pathology.
Duplex sonography of the carotid arteries in patients with isolated aortic stenosis: imaging findings and relation to severity of stenosis.
OBJECTIVE: The purposes of this study were to identify carotid artery duplex waveform abnormalities in patients with isolated aortic stenosis and to determine whether waveform abnormalities correlate with the severity of valvular disease. MATERIALS AND METHODS: Twenty-four patients with various degrees of aortic stenosis diagnosed by echocardiography and/or cardiac catheterization had preoperative carotid artery duplex sonograms that were retrospectively reviewed for acceleration time, peak velocity, waveform contour, upstroke delay, and presence of a dicrotic notch and a second systolic peak. Data were collected for the right and left internal, external, and common carotid arteries separately. These findings were correlated with aortic valve area and compared with data for a control group of 11 age-matched patients with normal echocardiographic findings. Two additional patients with isolated aortic stenosis diagnosed by echocardiography and/or cardiac catheterization were prospectively evaluated in a similar fashion, with acceleration time being calculated directly from the sonography unit. RESULTS: Unlike the patients with mild or moderate stenosis, the patients with critical or severe stenosis had a mean acceleration time that was significantly longer than that in the control subjects (p = .008-.0001). Peak velocities were decreased in all cases of aortic stenosis regardless of severity only in the common carotid arteries. All 13 patients with critical aortic stenosis had delayed upstrokes and rounded waveforms in the common, internal, and external carotid arteries. Twenty percent (one of five) of the patients with severe stenosis and 17% (one of six) of the patients with moderate or mild stenosis also had these characteristics. The two prospectively evaluated patients, who had critical and severe aortic stenoses, had similar findings. None of the control subjects showed these abnormalities. The presence or absence of a second systolic peak or a dicrotic notch was not different between patients with aortic stenosis and control subjects. CONCLUSION: Increased acceleration time, decreased peak velocity, delayed upstroke, and rounded waveform are characteristic abnormalities found in duplex sonographic studies of the carotid arteries in patients with aortic stenosis. The degree of each of these abnormalities correlates with the valve area. Patients with critical or severe aortic stenosis had findings significantly different from those in the control group. Patients with mild or moderate disease showed few or no sonographic abnormalities.
Adenosine radionuclide perfusion imaging in the preoperative evaluation of patients undergoing peripheral vascular surgery.
To define the clinical and adenosine test variables that predicted perioperative cardiac events, 122 patients who received adenosine radionuclide perfusion imaging before peripheral vascular surgery were reviewed. Events included pulmonary edema, an ischemic end point of acute myocardial infarction (AMI) or cardiac death. Five patients underwent coronary revascularization before the surgical procedure. Of the 117 remaining patients, 19 had pulmonary edema, 10 had an AMI, and 2 died after peripheral vascular surgery. Most of the patients (78%) were in an intermediate-risk group as indicated by the presence of > or = 1 clinical risk factor as defined by the Eagle criteria. The only predictor of perioperative pulmonary edema was a history of congestive heart failure (33% vs 4%; p = 0.002). No clinical variables predicted AMI or death. The adenosine variables that were univariate predictors of AMI and death were the number of reversible perfusion defects (1.75 +/- 1.84 vs 0.75 +/- 0.90; p = 0.001) and the number of coronary artery distributions with a radionuclide perfusion defect (1.33 +/- 0.64 vs 0.85 +/- 0.67; p = 0.022). The number of reversible perfusion defects was the only multivariate predictor of ischemic events (p = 0.017). The presence of > 1 reversible defect was associated with an increased frequency of ischemic events (68% vs 28%; p = 0.045). The sensitivity and specificity of > 1 reversible defect was 58% and 73%, respectively, with a positive and negative predictive value of 19% and 94%.(ABSTRACT TRUNCATED AT 250 WORDS)
Comparison of coronary angiographic findings during the first six hours of non-Q-wave and Q-wave myocardial infarction.
The angiographic features of non-Q-wave acute myocardial infarction (AMI) soon after symptom onset have not been previously reported. Accordingly, this study reviewed the coronary angiographic findings of 86 patients with AMI studied within 6 hours of symptom onset: 58 had Q-wave and 28 had non-Q-wave AMI. Patients with Q-wave and non-Q-wave AMI were comparable in terms of clinical characteristics, frequency of 1-vessel disease, and infarct-related artery location. Thrombus was observed in 49 patients (84%) with Q-wave AMI versus 12 (43%) with non-Q-wave AMI (p = 0.0002). Whereas complete occlusion of the infarct-related artery was present in 53 patients (91%) with Q-wave AMI, total coronary occlusion was present in only 11 (39%) with non-Q-wave AMI (p = 0.0001). Collaterals to occluded infarct arteries were seen in 10 patients (19%) with Q-wave AMI versus 5 (45%) with non-Q-wave AMI (p = 0.06). Residual perfusion of the infarct artery by either anterograde or collateral flow was typical of patients with non-Q-wave AMI (22 of 28, 79%) but was uncommon in those with Q-wave AMI (15 of 58, 26%) (p = 0.0001). Thus, coronary angiography performed within 6 hours of symptom onset demonstrates important differences between Q-wave and non-Q-wave AMI. Non-Q-wave AMI is characterized by partial perfusion of the infarct-related artery by either anterograde or collateral flow, and a lower incidence of thrombus than Q-wave AMI.(ABSTRACT TRUNCATED AT 250 WORDS)