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Biomedical subjects

M W Krucoff

Publications and source records attributed to M W Krucoff.

At least 55 records · Page 3Linked to original sources
PubMed1994

Randomized evaluation of coronary angioplasty for early TIMI 2 flow after thrombolytic therapy for the treatment of acute myocardial infarction: a new look at an old study. The Thrombolysis and Angioplasty in Myocardial Infarction (TAMI) Study Group.

BACKGROUND: Patients who have suffered acute myocardial infarction (AMI) and have been treated with intravenous thrombolytic agents resulting in early 'patent' [Thrombolysis in Myocardial Infarction (TIMI) 2-3 flow grade] arteries have been shown not to benefit from early percutaneous transluminal coronary angioplasty (PTCA). Recent data, however, suggest that the clinical outcome of patients with early TIMI 2 flow is decidedly inferior to that of patients with TIMI 3 flow, raising the question whether early PTCA might be beneficial for patients with TIMI 2 flow. The clinical utility of PTCA for this particular subset of patients has never been assessed. METHODS: We analyzed left ventricular ejection fraction (LVEF) recovery by contrast ventriculography and clinical outcome in Thrombolysis and Angioplasty in Myocardial Infarction Phase I (TAMI-I) study patients with initial TIMI 2 flow grade, determined by blinded core laboratory analysis. RESULTS: No differences were observed between baseline demographic data for the 49 patients randomly assigned to undergo early PTCA compared with that from the 59 patients randomly assigned to receive early medical therapy. Patients were 56 +/- 11 years of age (mean +/- SD), 80% were men, the time from onset of chest pain to catheterization was 268 +/- 71 min, 42% had anterior AMI, and 42% had multivessel disease. Ninety minute baseline LVEF to prehospital discharge LVEF was minimally better in the group randomly assigned to undergo PTCA (51 +/- 12 to 52 +/- 11% versus 55 +/- 10 to 53 +/- 12%, P = 0.06). This contrasted with findings in patients with TIMI 3 flow grade at baseline, which showed a relative benefit for patients randomly assigned to receive early medical therapy (54 +/- 10 to 54 +/- 8% for PTCA, versus 55 +/- 10 to 58 +/- 8% for medical therapy, P = 0.01). Among patients with TIMI 2 flow grade there were no differences in in-hospital death or congestive heart failure (6.1 versus 1.7%, P = 0.25 and 18.4 versus 23.7%, P = 0.50, PTCA versus medical therapy, respectively). CONCLUSION: We conclude that (1) PTCA of infarct-related arteries with TIMI 2 flow grade may modestly improve recovery of left ventricular function, and (2) widespread application of PTCA in this setting should be deferred, pending demonstration that this benefit outweighs the risks of PTCA.

Aged↗
PubMed1994

The impact of autoperfusion on quantitative electrocardiographic parameters of ischemia severity, extent, and "burden" during salvage of elective coronary angioplasty.

Long angioplasty inflations have been reported using an autoperfusion system that delivers oxygenated blood distal to the balloon segment. The safety and efficacy of this system has been demonstrated in anatomically selected patients. The clinical use, however, is frequently to stabilize intimal dissection in unselected patients. We reviewed 12-lead continuous electrocardiographic (ECG) recordings in 40 patients in whom prolonged salvage with autoperfusion was attempted. Sub-optimal results were stabilized in 36 of 40, while 4 patients had urgent bypass. The presence of ischemia, as > or = 100 uV ST elevation over the 12 lead ECG, and the total ST deviation over all leads over the entire inflation period (total ischemic "burden") were compared within each patient between the longest standard balloon and autoperfusion inflations. Median duration of inflation was 3.03 min. with balloon vs. 15.6 min. with autoperfusion (p < 0.00002). Of the 40 patients, 35 (87%) had ECG ischemia with balloon vs. 18 (45%) with autoperfusion (p < .00002). Median severity of peak ST deviation was 321 uV with balloon vs. 132 uV with autoperfusion (p = 0.0001). Median extent of ST elevation was 3 leads with balloon vs. 0 leads with autoperfusion (p = 0.0001). Median total ischemic burden was similar with balloon (1173 uVmin) and autoperfusion (1083 uVmin, NS) despite the fivefold longer inflation duration with autoperfusion. Thus, in patients selected by clinical necessity rather than optimal anatomy, severity and extent of ST elevation were significantly reduced, although not entirely eliminated, by autoperfusion.

Angioplasty, Balloon, Coronary↗
PubMed1993

Treatment of long coronary artery narrowings with long angioplasty balloon catheters.

Balloon angioplasty of long coronary artery narrowings has been associated with a lower rate of acute success, and a higher rate of acute complications and restenosis than that observed for short narrowings. Angioplasty catheters with longer length balloons (30 and 40 mm) are now available, and the objective of this study was to determine the acute and long-term success for patients with long coronary artery narrowings treated with these longer balloons. All patients with long narrowings (> or = 10 mm) treated with long balloons at 1 institution over a 1-year period were identified (93 narrowings in 89 patients), and acute and long-term outcomes were carefully documented. Procedural success (residual stenosis < or = 50%) was 97%. Abrupt closure occurred in 6% and major dissection in 11% of narrowings. Clinical success (procedural success without in-hospital death, bypass surgery or myocardial infarction) was achieved in 90% of patients. Repeat catheterization was performed in 61 patients (76% of those eligible), and restenosis was found in 50 to 55%, depending on the definition used. The treatment of long coronary artery narrowings using angioplasty catheters with longer balloons leads to high rates of acute success. However, there is a high rate of restenosis. New interventional devices for long lesions should be compared with long balloons in a randomized controlled trial.

Aged↗
PubMed1993

Continuously updated 12-lead ST-segment recovery analysis for myocardial infarct artery patency assessment and its correlation with multiple simultaneous early angiographic observations.

Early angiography may not adequately subgroup patients with myocardial infarction if cyclic changes in coronary flow occur frequently. From a pilot experience using a new 12-lead ST-segment monitor, a continuously updated, self-referenced ST-recovery analysis method was developed to quantify both instantaneous recovery, as a noninvasive marker of patency, and cumulative ST recovery over time, as a marker of the speed, stability and duration of reperfusion. In 22 patients with acute infarction in whom 44 observations of unique angiographic patency were noted within 6 hours of presentation, serial patency assessments simultaneous with all angiographic observations predicted coronary occlusion with 90% sensitivity and 92% specificity. Of the 22 patients, 11 (50%) had multiple ST trend transitions suggesting cyclic changes in coronary flow before catheterization. Speed, stability and duration of ST-segment recovery were defined by the time to first 50% ST recovery, total number of ST-trend transitions and patent physiology index (percentage of monitoring period showing ST recovery), respectively. Subgrouped angiographically, the median (interquartile range) for cumulative ST parameters with patent (n = 8) versus occluded (n = 14) arteries were, respectively--time to 50% recovery, 1.57 (1.16, 1.70) versus 0.17 (-0.47, 0.32) hours; number of reelevation/recovery events, 1.5 (1, 3) versus 3 (1, 3); and patent physiology index, 52 (47, 59) versus 50 (5, 73). Thus, continuous ST-segment recovery analysis appears to predict simultaneous angiographic patency over serial assessments, whereas cumulative parameters appear to contain independent information, probably because of patency changes before or after angiography.

Cardiac Catheterization↗
PubMed1993

Clinical applications of coronary sinus retroperfusion during high risk percutaneous transluminal coronary angioplasty.

OBJECTIVES: This study was designed to determine the efficacy of synchronized coronary sinus retroperfusion of arterial blood in reducing myocardial ischemia associated with the performance of high risk coronary angioplasty. BACKGROUND: Previous animal and clinical work has demonstrated the efficacy of this technique in supporting ischemic myocardium. METHODS: Twenty-one patients were randomized to alternately receive coronary sinus retroperfusion support during either the second or the third coronary angioplasty balloon inflation, after an initial unsupported brief control inflation. Myocardial ischemia was assessed by the extent of echocardiographic left ventricular wall motion abnormality, quantified ST segment deviation and hemodynamic and anginal variables during balloon inflations performed with and without coronary sinus retroperfusion support. Regional wall motion score was defined as hyperkinesia (-1), normokinesia (0), hypokinesia (+1), akinesia (+2) and dyskinesia (+3). RESULTS: A reduction in the echocardiographic left anterior descending regional wall motion score in retroperfusion-supported (1.7 +/- 2.1) versus unsupported (2.7 +/- 1.6) inflations (p < 0.05) was noted. Twelve-lead electrocardiographic monitoring revealed no additional ST segment deviation during supported (173 +/- 95 s) compared with unsupported (129 +/- 87 s) angioplasty inflations despite a significantly longer duration of supported inflations (p < 0.004). Mean and peak systolic coronary sinus pressures differed during supported inflations (21 +/- 6 and 44 +/- 13 mm Hg) versus unsupported inflations (10 +/- 4 and 16 +/- 5 mm Hg) (p < 0.001). There was no difference in hemodynamic or anginal variables. CONCLUSIONS: A reduction in ischemia as defined by wall motion abnormality during retroperfusion-supported compared with unsupported angioplasty balloon inflations was documented. No additional ST segment deviation occurred during retroperfusion-supported compared with unsupported balloon inflations despite a significantly longer duration of supported inflations. No difference in hemodynamic or anginal variables was noted.

Adult↗
PubMed1993

Continuous 12-lead ST-segment recovery analysis in the TAMI 7 study. Performance of a noninvasive method for real-time detection of failed myocardial reperfusion.

BACKGROUND: If a practical, reliable, noninvasive marker of failed reperfusion was available in real time, the benefits of further therapy in this patient subgroup could be tested. We developed a method of 12-lead ST-segment recovery analysis using continuously updated reference points to provide such a marker. METHODS AND RESULTS: In this study, our method was prospectively tested in 144 patients given thrombolytic therapy early in myocardial infarction. All patients had 12-lead continuous ST-segment monitoring and acute angiography, each analyzed in an independent, blinded core laboratory. ST-segment recovery and re-elevation were analyzed up to the moment of angiography, at which time patency was predicted. Predictions were correlated to angiographic infarct artery flow, with TIMI flow 0 to 1 as occluded and TIMI flow 2 to 3 as patent. Infarct artery occlusion was seen on first injection in 27% of patients. The positive predictive value of incomplete ST recovery or ST re-elevation by our method was 71%, negative predictive value 87%, with 90% specificity and 64% sensitivity for coronary occlusion. ST recovery analysis predicted patency in 94% of patients with TIMI 3 flow versus 81% of patients with TIMI 2 flow and predicted occlusion in 57% of patients with collateralized occlusion versus 72% of patients with non-collateralized occlusion. In a regression model including other noninvasive clinical descriptors, ST recovery alone contained the vast majority of predictive information about patency. CONCLUSIONS: In a blinded, prospective, angiographically correlated study design, 12-lead continuous ST-segment recovery analysis shows promise as a practical noninvasive marker of failed reperfusion that may contribute substantially to currently available bedside assessment. Our data also suggest that patients with TIMI 2 flow or with collateralized occlusions may represent a physiological spectrum definable with ST-segment recovery analysis.

Adolescent↗
PubMed1993

ST-segment recovery as an endpoint in acute myocardial infarction trials. Past, present, and future.

Traditional, comparative acute myocardial infarction trials have used morbidity and mortality as endpoints, requiring large study populations. Left ventricular function and angiographic infarct-related artery patency have, therefore, been used as alternative endpoints. These assessments are costly, risk-laden, and put a large demand on resources not available in every hospital. This has led to an increased interest in noninvasive endpoints for comparative trials. This study describes the history and possibilities of ST-segment recovery analysis as an endpoint in acute myocardial infarction trials.

Electrocardiography↗
PubMed1992

Evolution of an automated ST-segment analysis program for dynamic real-time, noninvasive detection of coronary occlusion and reperfusion.

Patients in whom early and stable reperfusion through the infarct artery fails after thrombolytic treatment might benefit from further revascularization therapy. A reliable noninvasive technique able to detect both reperfusion and reocclusion would be useful to test this hypothesis. However, no such technique presently exists. ST-segment recovery analysis using continuous digital 12-lead ST monitoring has been shown to be an accurate predictor of infarct artery patency in real time. This method was dependent on a trained clinician's analysis of the recordings on a personal computer. For optimal bedside application, salient principles of this ST-segment recovery analysis were converted into algorithms and built into the ST monitor software. The essentials of these algorithms are described in this report.

Electrocardiography↗
PubMed1992

Prospective analysis of possible myocardial damage or hemolysis occurring as a result of prolonged autoperfusion angioplasty in humans.

OBJECTIVES: The purpose of this study was to further explore the procedural safety of prolonged (15-min) dilation using an autoperfusion coronary angioplasty balloon by assessing the degree of myocardial damage or hemolysis, if any, occurring as a result of the procedure. BACKGROUND: Prolonged balloon inflation periods may be beneficial during percutaneous transluminal coronary angioplasty. The duration of standard balloon angioplasty is often limited by the occurrence of myocardial ischemia due to loss of anterograde blood flow. Autoperfusion angioplasty allows continued myocardial perfusion during balloon inflation and has previously been shown to reduce but not totally eliminate acute myocardial ischemia during prolonged (up to 15 min) balloon inflation. The risk of intravascular hemolysis as a result of autoperfusion angioplasty has not yet been fully delineated. METHODS: Sixty-two consecutive patients (76% men; mean age 58 years) undergoing elective percutaneous transluminal coronary angioplasty of a single lesion were studied. Serial electrocardiographic and creatine kinase MB isoenzyme data were examined to detect evidence of myocardial damage. Tests for hemolysis (plasma free hemoglobin, serum haptoglobin and serum lactate dehydrogenase) were obtained in the 1st 24 consecutive patients. RESULTS: Inflation time was 14 +/- 4 min (mean +/- SD) and the procedure was successful (less than or equal to 50% residual lesion stenosis) in 59 patients (95%). Electrocardiographic evidence of myocardial infarction (greater than 1 mm persistent ST segment depression, greater than 1 mm ST segment elevation or new Q waves) was not observed in any patient. Cardiac enzyme assays were within the normal range in all patients. No evidence of hemolysis was found in the 24 consecutive patients studied. CONCLUSIONS: We conclude that prolonged autoperfusion angioplasty can be performed in patients without clinical evidence of myocardial damage or hemolysis.

Aged↗
PubMed1991

Quantification of ST-segment changes during coronary angioplasty in patients with left bundle branch block.

Electrocardiographic manifestations of ischemia are difficult to interpret in the presence of left bundle branch block (LBBB). Recently developed techniques allow continuous computerized digital analysis of ST segments that can be zeroed to the patient's own baseline electrocardiogram even if that baseline is abnormal conduction. With use of this technology, ST-segment changes during balloon coronary occlusion were compared in 10 patients with LBBB versus an age-, sex-, and coronary anatomy-matched population of 20 control subjects with normal baseline conduction. ST-segment deviation of greater than or equal to 1 mm from baseline was present in 80% of patients with LBBB and in 75% of control patients (difference not significant). There was no significant difference between patients with LBBB versus control patients in maximal ST-segment deviation (2.6 +/- 1.7 vs 2.0 +/- 1.0 mm) or in ST-segment deviation measured after 60 seconds of occlusion (2.4 +/- 1.3 vs 1.8 +/- 1.1 mm). ST-segment deviation reached 1 mm more quickly in patients with LBBB (33 +/- 11 seconds) than in control subjects (60 +/- 36 seconds) (p = 0.003). It is concluded that ST-segment analysis is feasible in patients with LBBB using digital self-referenced ST analysis and may provide important clinical information regarding the presence of myocardial ischemia.

Angioplasty, Balloon, Coronary↗
PubMed1990

Reduction of myocardial ischemia during percutaneous transluminal coronary angioplasty with oxygenated Fluosol.

The effects of perfusion of an oxygen-carrying perfluorochemical emulsion (Fluosol) in alleviating symptoms of myocardial ischemia during balloon occlusion were examined in a multicenter trial of 245 patients. Severe anginal pain occurred less frequently in patients receiving Fluosol perfusion (21%) than in those receiving routine angioplasty (34%) (p less than 0.05). ST-segment changes at balloon deflation in routine angioplasty patients were significantly greater than in patients who received oxygenated Fluosol perfusion (2.2 +/- 1.2 vs 1.7 +/- 0.9 mm; p less than 0.03). Profound regional wall dysfunction (-561 +/- 224 U) was observed in routine angioplasty patients by 2-dimensional echocardiography. Patients receiving oxygenated Fluosol perfusion, however, maintained near baseline levels of ventricular function (-61 +/- 335 U) during occlusion (p less than 0.0001). Mean global left ventricular ejection fraction was preserved at baseline levels during balloon inflation in patients perfused with oxygenated Fluosol but decreased significantly (p less than 0.001) during occlusion in routine angioplasty patients. A total of 26 complications (19 routine group; 7 perfusion group) was reported. Adverse responses to the perfusate were infrequent, occurring in 1.6 and 2.0% of patients after the test dose and during perfusion, respectively. Thus, transcatheter perfusion with an oxygen-carrying perfluorochemical emulsion is effective in alleviating myocardial ischemia during angioplasty and can be safely administered in this patient population.

Aged↗
PubMed1990

The portable programmable microprocessor-driven real-time 12-lead electrocardiographic monitor: a preliminary report of a new device for the noninvasive detection of successful reperfusion or silent coronary reocclusion.

Successful intravenous thrombolytic therapy early in myocardial infraction has the potential to reduce patient mortality without the additional risk and cost of aggressive invasive therapy. Noninvasive detection of successful reperfusion using resolution of chest pain, ST-segment changes assessed on static electrocardiograms, arrhythmia evolution, early isoenzyme peaking or changes in ventricular perfusion or function has been hampered by poor sensitivity or specificity, or inability to provide timely information. A newly available portable programmable microprocessor-driven real-time 12-lead electrocardiographic monitor has been introduced that may address these limitations. A continuously updated precise digital record of ST-segment activity at the bedside provides valuable information both in monitoring patients during reperfusion therapy to determine the efficacy of such treatment and in the subsequent hours to signal threatened reocclusion. This report describes the salient features of the monitor and presents 4 distinct situations in which the monitor detected timely information regarding coronary patency after reperfusion.

Angioplasty, Balloon, Coronary↗