Biomedical subjects

D D Waters

Publications and source records attributed to D D Waters.

At least 37 records · Page 2Linked to original sources

PubMed1999

Clinical and angiographic characteristics of exertion-related acute myocardial infarction.

CONTEXT: Vigorous physical exertion transiently increases the risk of acute myocardial infarction (MI), but little is known about the clinical characteristics of exertion-related MI. OBJECTIVE: To compare the clinical and angiographic characteristics of patients who had an exertion-related acute MI vs those who experienced an MI not related to exertion. DESIGN AND SETTING: Prospective observational cohort study of patients with an acute MI referred to a tertiary care hospital for primary angioplasty. PATIENTS: Of 1048 patients with acute MI, 640 (64 who experienced an exertion-related MI and 576 who did not) were selected for treatment with primary angioplasty and admitted between August 1995 and November 1998. MAIN OUTCOME MEASURES: Clinical characteristics of the patients, including their habitual physical activity (determined by the Framingham Physical Activity Index and the Lipid Research Clinic Physical Activity Questionnaire), angiographic findings during coronary angiography, and the relative risk (RR) of MI during exertion. RESULTS: Patients who experienced exertion-related MI were more frequently men (86% vs 68%), hyperlipidemic (62% vs 40%), and smokers (59% vs 37%), were more likely to present with ventricular fibrillation (20% vs 11%), Killip classification III or IV heart failure (44% vs 22%), single-vessel disease (50% vs 28%), and a large thrombus in the infarct artery (64% vs 35%) and were more likely to be classified as having very low or low activity (84% vs 66%). The RR of experiencing an MI during exertion was 10.1 times greater than the risk at other times (95% confidence interval [CI], 1.6-65.6), with the highest risk among patients classified as very low active (RR, 30.5; 95% CI, 4.4-209.9) and low active (RR, 20.9; 95% CI, 3.1-142.1). CONCLUSION: These results show that exertion-related MIs occur in habitually inactive people with multiple cardiac risk factors. These individuals may benefit from modest exercise training and aggressive risk-factor modification before they perform vigorous physical activity.

Cardiac Catheterization↗

PubMed1999

Impact of limited treadmill exercise on adenosine Tc-99m sestamibi single-photon emission computed tomographic myocardial perfusion imaging in coronary artery disease.

Limited exercise combined with dipyridamole increases myocardial perfusion defect severity compared with dipyridamole alone. The impact of limited exercise combined with adenosine on myocardial perfusion defect severity is unknown. This study compares myocardial perfusion defect severity with adenosine alone and adenosine combined with limited exercise. Thirty-two patients with coronary artery disease underwent on separate days and in randomized order technetium-99m sestamibi (25 to 30 mCi) single-photon emission computed tomographic imaging at rest, after adenosine (140 microg/kg/min x 6 minutes), and after adenosine (140 microg/kg/min x 4 minutes) during 6 minutes of modified Bruce treadmill exercise (adenosine-exercise). Radiopharmaceutical was injected at 3 and 5 minutes during adenosine and adenosine-exercise, respectively. Images were interpreted by a consensus agreement of 3 nuclear cardiologists without knowledge of patient identity, stress protocol, or clinical data using a 17-segment model and 5-point scoring system. A summed stress score (SSS), summed rest score (SRS), and summed difference (SSS-SRS) score (SDS) were calculated for each image. Peak stress heart rate and rate-pressure product were higher for adenosine-exercise than adenosine (102 +/- 19 vs 81 +/- 11 beats/min and 13,972 +/- 4,265 vs 10,623 +/- 2,131, respectively; both p <0.001). Sensitivity for detection of > or = 50% coronary stenosis was 75% and 72% for adenosine-exercise and adenosine, respectively (p = NS). There were no differences in SSS and SDS between adenosine-exercise and adenosine (8.2 +/- 5.9 vs 8.1 +/- 6.3 and 4.9 +/- 4.1 vs 5.2 +/- 4.6, respectively; both p = NS). Thus, in patients with coronary artery disease, limited treadmill exercise combined with adenosine does not increase myocardial perfusion defect severity compared with standard adenosine technetium-99m sestamibi single-photon emission computed tomographic myocardial perfusion imaging.

Adenosine↗

PubMed1999

Management strategies in unstable coronary artery disease--current problems and future directions. The UCAD Council.

Unstable coronary artery disease continues to pose a major challenge to clinicians. The advent of new therapies, such as percutaneous transluminal coronary angioplasty, low-molecular-weight heparins, and glycoprotein IIb/IIIa inhibitors, provides new management options for this indication but also raises new questions with regard to optimal management. Prospective randomized trials with well-defined, long-term outcome measures and a means of identifying which patients will derive most benefit from each treatment, together with a means of rapid and clear dissemination of study results and implications, are required in order to advance the management of unstable coronary artery disease.

Angina, Unstable↗

PubMed1999

Enhanced local intracoronary delivery of heparin with the Infiltrator catheter: a comparative study.

The efficacy of local drug delivery in the treatment of coronary artery disease is limited by the relatively low delivery efficiency of the available devices. A unique local drug delivery device, the Infiltrator catheter (InterVentional Technologies, Inc.), has been designed specifically to enhance efficiency by injecting drugs directly into the arterial wall through microports mounted on the balloon surface. The purpose of this study was to assess the efficiency of delivery of this device in the porcine coronary model and to compare it to a previously validated device, the hydrogel balloon (Boston Scientific, Maple Grove, Minnesota). Studies were also performed to assess the pattern of intramural heparin deposition following delivery with the Infiltrator catheter and to assess the effect of the microports on vascular integrity. The efficiency of delivery was significantly greater with the Infiltrator catheter than with the hydrogel balloon (4.5% vs. 0.08%; p = 0.02). Similarly, the absolute amount of intramurally deposited heparin was greater with the Infiltrator (111.3 +/- 38.5 units vs. 2.4 +/- 0.85 units; p = 0.02) despite the fact that more heparin was delivered with the hydrogel catheter. Histologic studies revealed characteristic discrete puncture channels in the vessel wall due to penetration of the microports. Other than this histologic finding, there was no significant difference in the extent of architectural disruption between the Infiltrator and conventional balloon inflations. Fluorescein-labeled heparin studies revealed heparin to be diffusely distributed throughout the vessel wall immediately following delivery with the Infiltrator. We conclude that the Infiltrator catheterOs unique mechanism of delivery improves the efficiency of local drug delivery without excessive vessel wall trauma.

Animals↗

PubMed1998

Combined assessment of myocardial perfusion and left ventricular function with exercise technetium-99m sestamibi gated single-photon emission computed tomography can differentiate between ischemic and nonischemic dilated cardiomyopathy.

The purpose of this study was to determine whether exercise technetium-99m sestamibi gated single-photon emission computed tomography (SPECT) accurately distinguishes between patients with ischemic cardiomyopathy and patients with nonischemic left ventricular systolic dysfunction. Noninvasive tests have previously failed to accurately separate patients with ischemic cardiomyopathy from those with nonischemic cardiomyopathy. Technetium-99m gated SPECT imaging offers advantages that have the potential to overcome the limitations of previous studies. Thirty-seven adults with a left ventricular ejection fraction < or = 35%, including 24 patients with nonischemic cardiomyopathy and 13 patients with ischemic cardiomyopathy, were prospectively evaluated using symptom-limited metabolic exercise treadmill testing with technetium-99m sestamibi gated SPECT imaging. Interpretation of myocardial perfusion and regional wall motion was performed, using a 17-segment model. Summed stress, rest, and reversibility perfusion defect scores were determined, and the variance of segmental wall motion scores was computed. Summed stress, rest, and reversibility perfusion defect scores were significantly lower in nonischemic cardiomyopathy patients, compared with those with ischemic cardiomyopathy (summed stress defect score: 6.9 +/- 3.8 vs 32.9 +/- 7.7, respectively, p <0.001). Variability in segmental wall motion was also significantly lower in patients with nonischemic cardiomyopathy compared with those with ischemic cardiomyopathy (variance: 0.3 +/- 0.3 vs 1.2 +/- 0.8, respectively, p <0.001). Thus, assessment of myocardial perfusion and regional ventricular function with exercise technetium-99m sestamibi gated SPECT imaging can reliably distinguish between patients with ischemic cardiomyopathy and patients with nonischemic dilated cardiomyopathy.

Adult↗

PubMed1998

Oral estrogen improves serum lipids, homocysteine and fibrinolysis in elderly men.

The effects of estrogen on cardiovascular risk factors have been less well defined in men than in women. We measured lipid and lipoprotein concentrations, lipoprotein particle size distributions, lipoprotein (a), homocysteine, and markers of thrombosis and fibrinolysis in 18 [corrected] healthy elderly men (age 74 +/- 3 years, mean +/- S.D.) before and after 9 weeks of treatment with 0.5, 1 or 2 mg/day of oral micronized 17beta-estradiol. LDL-C (-6%), apo B (-9%), triglyceride (-5%), and homocysteine (-11%) concentrations decreased with estradiol, whereas HDL-C (+14%) increased. Intermediate-size VLDL subclass concentrations were lowered and LDL and HDL subclass levels altered in such a way as to cause average LDL and HDL particle size to increase. Lipoprotein (a) did not change. Fibrinogen (-13%) and plasminogen activator inhibitor-1 (PAI-1) concentrations (-26%) decreased, but there were no changes in thrombotic markers including thrombin-antithrombin III complex, prothrombin fragment 1.2, D-dimer, antithrombin activity, protein-C and S and von Willebrand factor antigen. Breast tenderness occurred in four men and heartburn in five but did not require discontinuation of treatment. We conclude that oral estrogen in men reduces homocysteine, fibrinogen, and PAI-1 concentrations and favorably influences VLDL, LDL and HDL subclass levels without increasing markers of thrombotic risk.

Administration, Oral↗

PubMed1998

Abciximab in primary coronary angioplasty for acute myocardial infarction improves short- and medium-term outcomes.

OBJECTIVES: The purpose of this study was to compare the outcome of primary percutaneous transluminal coronary angioplasty for acute myocardial infarction (MI) when performed with or without the platelet glycoprotein IIb/IIIa antibody, abciximab. BACKGROUND: Abciximab improves the outcome of angioplasty but the effect of abciximab in primary angioplasty has not been investigated. METHODS: Data were collected from a computerized database. Follow-up was by telephone or review of outpatient or hospital readmission records. RESULTS: A total of 182 consecutive patients were included; 103 received abciximab and 79 did not. The procedural success rate was 95% in the two groups. At 30-day follow-up, the composite event rate of unstable angina, reinfarction, target vessel revascularization and death from all causes was 13.5% in the group of patients who did not receive abciximab, 4% (p < 0.05) in the abciximab group and 2.4% (p < 0.05) in the subgroup of patients (n = 87) who completed the 12-h abciximab infusion. At the end of follow-up (mean 7+/-4 months), the composite event rate was 32.4%, 17% (p < 0.05) and 13.1% (p < 0.01) in these three categories respectively. Abciximab bolus followed by a 12-h infusion was an independent predictor of event-free survival, in a Cox proportional hazards model (relative risk 0.49; 95% confidence interval 0.24 to 0.99; p < 0.05). CONCLUSIONS: Abciximab given at the time of primary angioplasty may improve the short- and medium-term outcome of patients with acute MI, especially when a 12-h infusion is completed.

Abciximab↗

PubMed1998

Comparison of cardiac troponin I, creatine kinase-MB, and myoglobin for detection of acute ischemic myocardial injury in a swine model.

To study the comparative value of the levels of cardiac troponin I (cTnI), creatine kinase-MB isoenzyme (CK-MB), and myoglobin in the detection of acute ischemic myocardial injury, we serially measured plasma concentrations of these cardiac proteins in 12 pigs with myocardial ischemia subtending severe coronary artery stenoses and in 5 pigs with a sham operation performed, but without coronary artery stenosis. In the stenosis group, flow in the left anterior descending (LAD) artery was reduced by 36% and maintained for 24 hours (n = 3), 7 days (n = 6), or 4 weeks (n = 3). Flow in the coronary artery was measured by a flowmeter, and regional left ventricular dysfunction was monitored by echocardiography. Myocardial infarction was identified with triphenyltetrazolium chloride staining. All pigs with stenosis of the LAD had significant ultrastructural abnormalities consisting of loss of myofibrils and an increase in mitochondria and glycogen deposition. Cardiac proteins were released in all pigs with stenosis of the LAD artery during the development of myocardial ischemia; the levels of cTnI, CK-MB, and myoglobin increased significantly relative to the baseline. The sensitivity and specificity for cTnI were higher than for CK-MB or myoglobin. Results of this study show that cTnI is the better marker for the detection of acute ischemic myocardial injury. Increased levels of cTnI can be found in reversible and irreversible myocardial ischemic injury in this model.

Acute Disease↗

PubMed1997

Nitroglycerin enhances the ability of dobutamine stress echocardiography to detect hibernating myocardium.

BACKGROUND: A biphasic response of wall thickening with initial improvement and subsequent deterioration during dobutamine stress echocardiography (DSE) has been increasingly used for detection of hibernating myocardium. However, the improvement of wall thickening at low-dose DSE may be limited in hibernating myocardium by severe hypoperfusion. Nitroglycerin (NTG) improves myocardial perfusion, reduces oxygen demand, and may enhance low-dose dobutamine to improve wall thickening. METHODS AND RESULTS: A pig model of myocardial hibernation of 24 hours to 7 days was created through severe left anterior descending coronary artery stenosis with coronary flow reductions of approximately 40%, producing severe regional left ventricular dysfunction but no infarction in seven pigs. Myocardial infarction was produced in five pigs with occlusion of the artery. DSE was performed with incremental doses with and without an NTG infusion of 50 to 100 microg/min. In the hibernating group, NTG alone improved wall thickening in the hibernating region modestly from 11.4+/-7.2% at baseline to 19.1+/-7.0%. The improvement was associated with increased regional coronary flow from 0.46+/-0.12 to 0.55+/-0.13 mL x beat(-1) x 100 g myocardium(-1) (P<.05). There was an additive effect of NTG to low-dose (2.5 to 5 microg x kg(-1) x min(-1)) dobutamine on wall thickening in the hibernating region. The improvement of wall thickening of hibernating myocardium with NTG and dobutamine, from 23.7+/-11.1% to 31.1+/-8.9% (P<.001), was associated with an increase in regional coronary flow (P<.01). NTG did not prevent high doses of dobutamine from inducing deterioration of wall thickening in hibernating myocardium. In the infarcted group, no improvement in wall thickening was observed in infarcted regions during NTG infusion, dobutamine infusion, or the combination. CONCLUSIONS: NTG enhances the improvement of wall thickening at low-dose dobutamine and does not prevent high-dose dobutamine from inducing ischemia in hibernating myocardium. Thus, NTG augments the biphasic response of wall thickening and improves the accuracy of DSE for detecting viable myocardium.

Animals↗

PubMed1997

Coronary angioplasty induces a systemic inflammatory response.

C-reactive protein (CRP) levels increased more than sixfold above baseline when measured 48 hours after elective percutaneous transluminal coronary angioplasty (PTCA) in patients without underlying inflammatory conditions and did not change significantly in controls undergoing coronary angiography. Only 3 of the 42 PTCA patients had clinical restenosis and underwent target vessel revascularization during the 6-month follow-up, but 2 of the 3 had very high CRP levels 48 hours after the procedure.

Angioplasty, Balloon, Coronary↗

PubMed1997

Left ventricular remodeling in myocardial hibernation.

BACKGROUND: Left ventricular (LV) remodeling as a consequence of extensive myocardial infarction has been well established in animal and human studies. This study was designed to determine whether regional LV dysfunction with myocardial hibernation without transmural or extensive infarction could initiate the remodeling process. METHODS AND RESULTS: A severe left anterior descending coronary artery stenosis was created to reduce resting flow by approximately 40% (from 0.99+/-0.10 to 0.56+/-0.11 mL x min(-1) x g[-1]) and was maintained for 7 days in 13 pigs. The reduction of regional coronary flow initially produced acute myocardial ischemia, as evidenced by reduced regional wall thickening, from 37+/-3% at baseline to 9+/-7%, regional lactate production and a decrease in regional coronary venous pH. All pigs had significant regional LV dysfunction and reduced LV ejection fraction (41+/-11%). The LV end-diastolic volume increased from 59+/-9 mL at baseline to 74+/-13 mL immediately after placement of the stenosis and to 78+/-17 mL 7 days later with hibernating myocardium. The LV mass did not change immediately (60+/-8 g baseline versus 59+/-11 g immediately after creation of the stenosis) but increased modestly yet significantly to 67+/-15 g after 7 days of myocardial hibernation subtending the severe LAD stenosis. The reductions of coronary flow and wall thickening were unchanged at 7 days, whereas myocardial lactate production recovered. By 4 weeks after restoration of LAD flow, regional function had recovered in all 7 pigs with follow-up. Of the 13 pigs, 6 were free from any evidence of myocardial infarction, and 4 had patchy necrosis involving less than 6% of the area at risk. CONCLUSIONS: LV remodeling, which is commonly associated with extensive myocardial infarction, can be initiated by regional dysfunctional hibernating myocardium resulting from a severe coronary stenosis. Myocardial necrosis is not a prerequisite for LV remodeling in response to regional dysfunction.

Animals↗

PubMed1997

Myocardial cell death and apoptosis in hibernating myocardium.

OBJECTIVES: This study was designed to study apoptosis in hypoperfused hibernating myocardium subtending severe coronary stenosis. BACKGROUND: Apoptosis contributes to myocyte death in acute myocardial infarction. METHODS: A left anterior descending coronary artery stenosis was created in 13 pigs and maintained for 24 h (n = 4), 7 days (n = 5) and 4 weeks (n = 4) to reduce coronary blood flow by a mean of 34% with severe regional myocardial systolic dysfunction, as documented by echocardiography. Apoptosis was detected with an in situ end-labeling method and confirmed by "deoxyribonucleic acid laddering" on agarose-gel electrophoresis. The severity of apoptosis was expressed as the percentage of apoptotic myocyte nuclei and nonapoptotic myocardial nuclei. RESULTS: Myocardial blood flow of the anterior left ventricular wall was reduced from 1.00 +/- 0.18 to 0.66 +/- 0.21 ml/min per g (p < 0.01), with a severe reduction of anterior regional wall thickening from a mean (+/-SD) of 39 +/- 4% to 9 +/- 8% (p < 0.01). There was no myocardial infarction in five pigs and minimal patchy infarction of < or = 6% of the area at risk in eight pigs. Apoptotic myocytes were observed in the hibernating myocardial region in all pigs (4.8 +/- 2.3%). Myocyte apoptosis was patchy in distribution and was found predominantly in the subendocardial myocardium (9.8 +/- 4.6%) and rarely in the subepicardial myocardium (0.32 +/- 0.45%). Apoptosis was found not only around focal fibrosis areas, but also in areas without fibrosis or patchy infarction. Apoptosis was found not only in 24-h hypoperfused myocardium, but also in 4-week hypoperfused myocardium. The severity of myocyte apoptosis correlated significantly with regional coronary blood flow reduction (r = 0.75, p < 0.01). No apoptosis was found in the normal control region. CONCLUSIONS: This study demonstrates that there is ongoing myocyte death through myocyte apoptosis in hypoperfused hibernating myocardium.

Animals↗

PubMed1997

Direct comparison of arbutamine and dobutamine stress testing with myocardial perfusion imaging and echocardiography in patients with coronary artery disease.

Arbutamine, a new sympathomimetic compound, appears to elicit a more balanced inotropic and chronotropic response than dobutamine, currently used as a pharmacologic stress agent. The present study was performed to compare standard dobutamine stress testing with arbutamine for the detection of myocardial ischemia with technetium (Tc)-99m sestamibi tomographic imaging and 2-dimensional echocardiography in patients with coronary artery disease. Twenty-six patients with evidence of coronary artery disease underwent dobutamine infusion of 5 to 40 microg/kg/min in 3-minute stages. On a separate day, arbutamine was administered by an automated, computerized, closed-loop device monitoring both heart rate and blood pressure. Both infusions were terminated upon achievement of target heart rate, completion of maximal infusion dose (dobutamine), heart rate saturation (arbutamine), or standard clinical end points. Tc-99m sestamibi was injected before termination of both infusions followed by tomographic myocardial perfusion imaging, whereas echocardiography was performed at baseline and throughout the infusions. There were no significant differences in maximal heart rate, blood pressure, and rate-pressure product as well as in the development of anginal symptoms or electrocardiographic changes during both infusions. The location and severity of myocardial perfusion defects and echocardiographic wall motion abnormalities were similar between both agents. It is concluded that arbutamine produces similar imaging results compared with standard dobutamine stress with both Tc-99m sestamibi single-photon emission computed tomographic myocardial perfusion imaging and 2-dimensional echocardiography.

Adult↗

PubMed1997

Impact of acute propranolol administration on dobutamine-induced myocardial ischemia as evaluated by myocardial perfusion imaging and echocardiography.

Beta-blocker therapy may delay or completely prevent myocardial ischemia during exercise testing, as assessed by ST-segment shifts, myocardial perfusion defects, or echocardiographic wall motion abnormalities. However, the impact of beta-blocker therapy on these end points during dobutamine stress testing has not been well established. The purpose of this study was to determine the impact of propranolol on dobutamine stress testing with ST-segment monitoring, technetium-99m (Tc-99m) sestamibi single-photon emission computed tomography (SPECT) imaging, and echocardiography. In 17 patients with known reversible perfusion defects, dobutamine stress tests with and without propranolol were performed in randomized order and on separate days, following discontinuation of oral beta blockers and calcium antagonists. Propronolol was administered intravenously to a cumulative dose of 8 mg or to a maximum heart rate reduction of 25% and dobutamine was infused in graded doses in 3 minute stages until a standard clinical end point or the maximum dose of 40 microg/kg/min was achieved. The dobutamine stress test after propranolol was associated with a lower maximum heart rate (83 +/- 18 vs 125 +/- 17, p <0.001) and rate pressure product (14,169 +/- 4,248 vs 19,894 +/- 3,985, p <0.001) despite a higher infusion dose. The SPECT myocardial ischemia score was also lower (6.9 +/- 5.8 vs 10.1 +/- 7.1, p = 0.047) and fewer echocardiographic segments were abnormal (3.4 +/- 3.0 vs 4.6 +/- 3.4, p = 0.042). In 4 of 17 patients, reversible perfusion defects and echocardiographic wall motion abnormalities were detected during the control but not during the propranolol test. Thus, during dobutamine stress testing, beta-blocker therapy attenuates, and in some cases eliminates, evidence of myocardial ischemia.

Aged↗

PubMed1997

Local delivery of c-myb antisense oligonucleotides during balloon angioplasty.

Intraluminal delivery of antisense oligonucleotides to c-myb was assessed following balloon angioplasty in swine peripheral arteries. Successful delivery and intramural persistence of oligonucleotide for over 24 h were demonstrated following angioplasty with hydrogel balloons coated with 32P-labeled antisense. Delivery of fluorescein-labeled antisense demonstrated further localization within the arterial media and intracellularly. Preliminary in vitro studies demonstrated the feasibility of inhibition of porcine lymphocyte proliferation using the murine antisense to c-myb. Twelve iliac or carotid arteries underwent angioplasty with antisense-coated balloons, while the contralateral vessels underwent angioplasty with the same-sized balloons coated with the complementary sense strand. Six to seven days later, dilated arterial segments were surgically isolated. In 10 of 12 vessel pairs, antisense-treated vessels demonstrated less cellular proliferation than did contralateral sense-treated vessels, as assessed by quantitative immunohistochemical staining of proliferating cell nuclear antigen, and smooth muscle cell proliferation was reduced 18% in antisense-treated vessels compared to the contralateral sense-treated vessels (PCNA-positive nuclear area: 7.7 +/- 4.9% vs. 9.3 +/- 5.2%, P < 0.04)-intraluminal delivery of antisense oligonucleotides to c-myb is feasible with a catheter-based system and may reduce smooth muscle cell proliferation following arterial injury.

Angioplasty, Balloon, Coronary↗

PubMed1997

Local delivery of heparin to balloon angioplasty sites with a new angiotherapy catheter: pharmacokinetics and effect on platelet deposition in the porcine model.

The purpose of this study was to assess the efficacy of local heparin delivery to balloon angioplasty sites in an in vivo porcine model by using a newly designed angiotherapy catheter that allows for prolonged drug infusion while maintaining distal arterial perfusion. Protocols were designed to assess the safety of intracoronary drug delivery, the effect of infusion time and drug concentration on intramural heparin deposition, the distribution of heparin within the arterial wall, the histologic effects of local heparin delivery, the wash-out of intramurally deposited heparin, and the effect of heparin delivery on early platelet deposition following balloon injury in peripheral and coronary vessels. Local intracoronary delivery of heparin was well tolerated in all animals. Between 0.04 and 0.08% of infused heparin was intramurally deposited at the time of drug delivery, with longer infusion durations and higher concentrations of heparin resulting in greater intramural deposition. Autoradiography demonstrated homogenous distribution of heparin throughout the intima, media, and adventitia, with localization in the nuclei, cytoplasm, and extracellular space. Histologic analysis demonstrated no additional vessel trauma from local drug delivery beyond that seen with conventional angioplasty. Wash-out studies demonstrated a biexponential disappearance of intramurally deposited drug, with rapid release of heparin over the first 60 min and persistence of small amounts of drug for at least 7 d. Locally delivered heparin significantly attenuated the deposition of platelets in peripheral vessels, although a similar decrease in platelet deposition in the coronary arteries was not statistically significant. Local delivery of heparin directly to coronary angioplasty sites is possible with the use of a new angiotherapy catheter. Wash-out of heparin from the arterial wall is initially rapid, although drug is detectable for up to 1 wk following delivery. In porcine peripheral arteries, use of this technique significantly decreases early platelet deposition following balloon injury.

Angioplasty, Balloon, Coronary↗

PubMed1997

Effect of low grade radiofrequency heating on arterial vasospasm in the porcine model.

Nineteen pigs were studied in order to assess the effect of low grade, radiofrequency-powered, thermal balloon angioplasty on the vasoconstrictor response of peripheral arteries. A mechanical stimulus was used to induce vasospasm. Thermal angioplasty reduced the extent of inducible vasospasm from 79% to 6% compared to nonthermal control inflations, which reduced the vasoconstrictor response from 75% to 60% (P < 0.001). Histologic studies demonstrated that the extent of myocyte necrosis was significantly greater in the thermally treated arteries than in the control vessels (P < 0.01). Thermal balloon angioplasty at 60 degrees C significantly attenuates peripheral arterial vasospasm induced by mechanical trauma in the porcine model. This paralytic effect may be related to the loss of myocytes secondary to thermal necrosis.

Angioplasty, Balloon↗

PubMed1997

Lupus-related mitral valve disease: embolic coronary occlusion as a unique cause of myocardial infarction.

Early diagnosis and greatly improved treatment have markedly altered the clinical evolution of systemic lupus erythematosus; the pattern of cardiac involvement in lupus has also changed. To illustrate this, a young woman who died from severe mitral valve disease, including a coronary embolus from verrucous endocarditis, is presented. Mitral valve involvement in lupus is no longer limited to the small benign lesions described by Libman and Sacks.

Adolescent↗