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Biomedical subjects

Morton J Kern

Publications and source records attributed to Morton J Kern.

At least 37 records · Page 2Linked to original sources
PubMed2005

Use of a new thrombus extraction catheter (the Pronto) in the treatment of acute myocardial infarction.

The finding of an intracoronary thrombus at the time of coronary angiography is common in patients presenting with an acute coronary syndrome. Pharmacologic and mechanical treatment strategies have been developed and reported to facilitate the treatment of the thrombus along with a percutaneous coronary intervention. We report a case in which a Pronto thrombectomy catheter was utilized to facilitate thrombus removal prior to the placement of a coronary stent in a patient who developed postinfarct angina and pulmonary edema after successful thrombolytic therapy for a acute ST segment elevation myocardial infarction.

Aged↗
PubMed2004

Lack of relation between imaging and physiology in ostial coronary artery narrowings.

This study compared ostial lesion angiographic severity with physiologic assessment and showed that, for diameter narrowings >70%, fractional flow reserves were >0.75 in 20 of 25 lesions and >0.75 in 30 of 30 lesions with <70% diameter narrowings. Using fractional flow reserve in all ostial narrowings > or =70% may prevent patients from undergoing unnecessary interventions.

Adenosine↗
PubMed2004

Coronary hyperemic dose responses of intracoronary sodium nitroprusside.

BACKGROUND: Sodium nitroprusside is one of several agents considered effective for treating the no-reflow phenomenon during acute coronary interventions. However, the coronary hyperemic dose responses and systemic hemodynamic effects of intracoronary nitroprusside have yet to be determined in humans. The purpose of this study was to compare the hyperemic and hemodynamic responses of intracoronary nitroprusside to intracoronary adenosine in patients during cardiac catheterization with angiographically normal anterior descending arteries. METHODS AND RESULTS: In 21 patients, coronary blood flow velocity (0.014-inch Doppler flow wire), heart rate, and blood pressure were measured in unobstructed left anterior descending coronary arteries at rest, after intracoronary adenosine (30- to 50-microg boluses), and after 3 serial doses (0.3-, 0.6-, and 0.9-microg/kg boluses) of intracoronary nitroprusside. Coronary reserve was calculated as hyperemia/basal coronary flow velocity. In an additional 9 patients with intermediate stenoses (53+/-7%), 14 fractional flow reserve (FFR) measurements (using 0.014-inch pressure wire) were performed with both intracoronary adenosine and nitroprusside (0.6 microg/kg). Intracoronary nitroprusside produced equivalent coronary hyperemia with a longer duration ( approximately 25%) compared with intracoronary adenosine. Intracoronary nitroprusside (0.9 microg/kg) decreased systolic blood pressure by <20%, with minimal change in heart rate, whereas intracoronary adenosine had no effect on these parameters. FFR measurements with intracoronary nitroprusside were identical to those obtained with intracoronary adenosine (r=0.97). CONCLUSIONS: Compared with adenosine, intracoronary nitroprusside produces an equivalent but more prolonged coronary hyperemic response in normal coronary arteries. Intracoronary nitroprusside, in doses commonly used for the treatment of the no-reflow phenomenon, can produce sustained coronary hyperemia without detrimental systemic hemodynamics. On the basis of FFR measurements compared with adenosine, sodium nitroprusside also appears to be a suitable hyperemic stimulus for coronary physiological measurements.

Adenosine↗
PubMed2004

Pulse transmission coefficient: a nonhyperemic index for physiologic assessment of procedural success following percutaneous coronary interventions.

Intracoronary pressure measurements and the determination of fractional flow reserve (FFR) after percutaneous coronary intervention (PCI) predict adverse events. Coronary lesions may impair the transmission of pressure waves across a stenosis, potentially acting as a high-frequency filter. The pulse transmission coefficient (PTC) is a nonhyperemic parameter that calculates the transmission of high-frequency components of the pressure signal through a stenosis. It was shown recently that PTC is highly correlated with FFR. This study was designed to examine the change of PTC as compared to FFR following PCI. Pressure signals were obtained by pressure guidewire in 27 lesions pre- and post-PCI and were analyzed with an algorithm that identifies the high-frequency component in the pressure signal. The PTC was calculated at baseline as the ratio between distal and proximal high-frequency components of the pressure waveform across the lesion. FFR measurements were assessed with intracoronary adenosine. There was a significant increase in PTC following PCI (0.15 +/- 0.17 at baseline vs. 0.84 +/- 0.11 post-PCI; P < 0.001). Comparable changes were observed for FFR (0.58 +/- 0.12 at baseline vs. 0.91 +/- 0.05 post-PCI; P < 0.001). PTC is a nonhyperemic parameter for physiologic assessment of coronary artery stenoses. Similar to FFR, PTC is significantly increased following PCI. Thus, it may serve as an adjunct index for the functional assessment of procedural success following PCI.

Aged↗
PubMed2004

Fallacy of thoracic side-branch steal from the internal mammary artery: analysis of left internal mammary artery coronary flow during thoracic side-branch occlusion with pharmacologic and exercise-induced hyperemia.

In some patients, myocardial ischemia after coronary artery bypass graft surgery has been attributed to a coronary steal phenomenon through a thoracic side branch originating from the left internal mammary artery (LIMA), even in the absence of subclavian or LIMA stenosis. To demonstrate that coronary flow through the LIMA is unchanged by occlusion of a LIMA side branch, we examined LIMA coronary flow velocity measurements (0.014" Doppler flow wire) in three patients at rest, during adenosine hyperemia, and again during hyperemia induced by left arm exercise before and again after the balloon occlusion of the thoracic side branch. For the three patients, no significant changes in resting or hyperemic flow were noted due to side-branch occlusion. Before side-branch occlusion, pharmacologic intra-arterial (adenosine) coronary flow reserve (hyperemic-to-basal flow velocity ratio) was 2.6, 1.5, and 3.2 and exercise flow reserve was 2.1, 1.3, and 1.2, respectively. After side-branch occlusion, pharmacologic coronary flow reserve was 2.5, 1.8, and 2.7 with exercise flow reserve of 1.8, 1.1, and 1.3, respectively. Under most ordinary circumstances, thoracic side-branch steal does not exist and that side-branch occlusion does not alter LIMA flow at rest or during pharmacologic or exercise-induced hyperemia. These data further suggest that a demonstration of the physiologic value of side-branch occlusion should precede surgical or percutaneous interruption of the thoracic artery in such patients.

Angina Pectoris↗
PubMed2004

Hemodynamic abnormalities across an anomalous left main coronary artery assessment: evidence for a dynamic ostial obstruction.

Anomalous left main coronary arteries have been associated with sudden cardiac death, especially when arising from the right coronary cusp and following an anterior course. To date, imaging procedures have been the mainstay of the decision-making process in determining which patients should undergo surgery for correction of this anomaly and which patients are presumed to be at low risk. We report on the hemodynamic evaluation of an anomalous left main performed in support of elected surgical correction in a young patient.

Adolescent↗
PubMed2004

The influence of obstructive sleep apnea on FFR measurements for coronary lesion assessment.

Fractional flow reserve (FFR) determinations have been demonstrated to be largely independent of changes in systemic hemodynamic changes. Herein, we describe a case of obstructive sleep apnea cyclically altering FFR measurements from normal to abnormal in a patient with an intermediately severe coronary narrowing following treatment for an acute coronary syndrome. To eliminate uncertainty, FFR measurements should be made if possible during suspended respiration.

Blood Flow Velocity↗
PubMed2004

Coronary pressure notch: an early non-hyperemic visual indicator of the physiologic significance of a coronary artery stenosis.

The disappearance of a dichrotic notch on the peripheral arterial pulse wave has been associated with significant peripheral vascular disease. A similar observation has not been reported in the distal coronary pressure waveform. The purpose of this study was to investigate the significance of a coronary pressure notch distal to a coronary stenosis and its relationship to fractional flow reserve. Ninety-seven patients with 131 angiographically indeterminate lesions (40-80% diameter narrowing) underwent FFR measurements for physiological significance. Hemodynamic tracings were recorded prior to the administration of adenosine and visually analyzed for the presence or absence of a dicrotic notch in the distal coronary artery pressure tracing. The stenoses were then divided into two groups based on the presence or absence of a notch. Of the 54 lesions without a distal coronary pressure notch, 31 had a FFR greater than or equal to 0.75 and of the 77 lesions with a notch, 75 had a FFR greater than or equal to 0.76. The sensitivity and specificity of a pressure notch was 94% and 74%, respectively, with positive and negative predictive values of 57% and 97%, respectively. The presence of a distal coronary pressure notch was predictive of a FFR greater than or equal to 0.76. The distal dicrotic pressure notch may be used as an additional parameter without requiring hyperemia for FFR measurements of uncertain clinical significance.

Age Factors↗
PubMed2003

Management of patients undergoing percutaneous coronary revascularization.

While performance of percutaneous coronary intervention (PCI) remains the domain of specialized cardiologists, patients undergoing PCI are cared for by noninvasive cardiologists, internists, and primary care physicians. Therefore, patient care is optimized when the entire patient care team understands procedural risks and complications as well as optimum patient management before, during, and after PCI. Before PCI, patients with contrast dye allergies should be identified and pretreated with steroids and an H1-blocker. Hydration should be initiated and maintained before and after the procedure to minimize the risks for contrast nephropathy. Periprocedure, patients should be monitored clinically for evidence of ischemia. In patients with significant groin, flank, abdominal, or back pain, as well as those with decrease in hematocrit or unexplained hypotension, the diagnosis of groin or retroperitoneal hematoma should be considered and promptly evaluated. Groin tenderness, pulsatile mass, or bruit should prompt evaluation for possible femoral pseudoaneurysm or arteriovenous fistulae. After the procedure, all patients treated with coronary stents should receive aspirin plus clopidogrel. Patients who develop typical anginal symptoms between the 1st and 6th to 8th months after PCI are likely to have restenosis and can be evaluated by an imaging study or repeated catheterization.

Angioplasty, Balloon, Coronary↗