R. David Anderson

Relationship Between Diabetes Mellitus and Long-term Survival After Coronary Bypass and Angioplasty

BACKGROUNDnRecent subgroup analyses of randomized trials have suggested that percutaneous intervention in diabetic patients with multivessel disease results in higher mortality than coronary artery bypass graft surgery (CABG). We studied the relationship between diabetes and survival after revascularization in a large prospective cohort of patients with multivessel coronary artery disease.nnnMETHODS AND RESULTSnBy analyzing data for 3220 patients (24% diabetic) with symptomatic two- or three-vessel coronary disease who were undergoing percutaneous transluminal coronary angioplasty (PTCA) or CABG at Duke University Medical Center between 1984 and 1990, we found that at 5 years, unadjusted survival in the group of patients undergoing CABG was 74% in diabetics and 86% in nondiabetics. Similarly, 5-year survival among PTCA patients was 76% in diabetics and 88% in patients without diabetes. After adjustment for baseline characteristics, diabetic patients receiving either PTCA or CABG had significantly poorer survival than nondiabetics (chi2=43.56, P<.0001). Unlike previous studies, however, there was no significant differential effect of diabetes on outcome between patients treated with PTCA and those treated with CABG (chi2=0.01, P=.91).nnnCONCLUSIONSnAlthough diabetes was associated with a worse long-term outcome after both PTCA and CABG in patients with multivessel coronary artery disease, the effect of diabetes on prognosis was similar in both treatment groups. Thus, our findings support the concept that the choice of initial revascularization strategy should not be based exclusively on a history of diabetes but rather should rely on other factors, such as angiographic suitability and clinical status.

Use of intraaortic balloon counterpulsation in patients presenting with cardiogenic shock: Observations from the GUSTO-I study

OBJECTIVESnWe sought to examine the use, complications and outcomes with early intraaortic balloon counterpulsation (IABP) in patients presenting with cardiogenic shock complicating acute myocardial infarction and treated with thrombolytic therapy.nnnBACKGROUNDnThe use of IABP in patients with cardiogenic shock is widely accepted; however, there is a paucity of information on the use of this technique in patients with cardiogenic shock who are treated with thrombolytic therapy.nnnMETHODSnPatients who presented within 6 h of chest pain onset were randomized to one of four thrombolytic regimens. Cardiogenic shock was not an exclusion criterion, and data for these patients were prospectively collected. Patients presenting with shock were classified into early IABP (insertion within one calendar day of enrollment) or no IABP (insertion on or after day 2 or never).nnnRESULTSnThere were 68 (22%) IABP placements in 310 patients presenting with shock. Early IABP use occurred in 62 patients (20%) and none in 248 (80%). Most IABP use occurred in the United States (59 of 68 IABP placements) involving 32% of U.S. patients presenting with shock. Despite more adverse events in the early IABP group and more episodes of moderate bleeding, this cohort showed a trend toward lower 30-day and 1-year mortality rates.nnnCONCLUSIONSnIABP appears to be underutilized in patients presenting with cardiogenic shock, both within and outside the United States. Early IABP institution is associated with an increased risk of bleeding and adverse events but a trend toward lower 30-day and 1-year all-cause mortality.

Does the presence of thrombus seen on a coronary angiogram affect the outcome after percutaneous coronary angioplasty? An angiographic trials pool data experience

OBJECTIVESnThis study aimed to determine whether pre-existing angiographic thrombus was associated with adverse in-hospital and six-month outcomes after percutaneous coronary interventions.nnnBACKGROUNDnThere are conflicting data about whether pre-existing thrombus is an independent predictor of adverse in-hospital and short-term outcome after coronary interventions.nnnMETHODSnThe Angiographic Trials Pool, a data set derived from eight prospective randomized trials, was analyzed. The study population consisted of 7,917 patients who underwent coronary interventions between 1986 and 1995. Two trials were excluded because they did not collect information regarding thrombus. Patients from the other six trials were divided on the basis of the presence or absence of thrombus.nnnRESULTSnIn patients with (n = 2,752) and without (5,165) thrombus, in-hospital mortality following angioplasty was low (0.8 vs. 0.6%, p = 0.207). Several adverse outcomes were higher in patients with thrombus: death/myocardial infarction (8.4 vs. 5.5%, p < or = 0.001), in-hospital abrupt closure (5.9 vs. 3.9%, p < or = 0.001) and an in-hospital composite of death, myocardial infarction and/or repeat revascularization (15.4 vs. 11.2%, p < or = 0.001). Six-month mortality was low and comparable between the two groups (2.1 vs. 1.8%, p = 0.34), but the incidence of six-month death/myocardial infarction was higher in patients with thrombus (11.7 vs. 8.7%, p < or = 0.0001).nnnCONCLUSIONSnPercutaneous coronary angioplasty can be performed with low mortality in patients with pre-existing thrombus, although these patients are at higher risk of in-hospital and six-month death/myocardial infarction. Continued efforts are required to optimize the outcome in these high risk patients.

Prognostic value of congestive heart failure history in patients undergoing percutaneous coronary interventions

OBJECTIVESnWe sought to determine the prognostic significance of a history of congestive heart failure above that provided by baseline ejection fraction in patients undergoing percutaneous coronary interventions.nnnBACKGROUNDnLeft ventricular function is a known predictor of survival in patients with coronary artery disease, as is a history of congestive heart failure. The contribution of heart failure history independent of left ventricular function is unknown.nnnMETHODSnData were pooled from four interventional trials and the Duke University database. The combined dataset included 5,260 patients undergoing percutaneous interventions, 334 with and 4,926 without a history of heart failure. Patients were defined by the treating physician as having a clinical history of heart failure at the time of enrollment.nnnRESULTSnThe 30-day and 6-month mortality were higher in patients with a clinical history of congestive heart failure than in those without such a history (2% vs. <1%, p=0.002 at 30 days, 5% vs. 1%, p=0.001 at 6 months). Heart failure history did not influence the incidence of myocardial infarction, use of angioplasty or the use of bypass surgery during follow-up. Multivariable analysis revealed that heart failure history added significantly to ejection fraction in predicting intermediate-term (6-month) mortality (p=0.01). Stepwise logistic regression also revealed heart failure history to be an independent predictor of 6-month mortality (odds risk 1.9, 95% confidence interval 1.1 to 3.5).nnnCONCLUSIONSnA clinical history of congestive heart failure is associated with increased early and intermediate-term mortality in patients undergoing percutaneous revascularization. Congestive heart failure history appears to provide prognostic information independent of that available from a patients left ventricular function. These findings suggest that patients with a clinical history of congestive heart failure who undergo a percutaneous intervention should be closely monitored, especially those with the lowest ejection fractions.

The effect of intra-aortic balloon counterpulsation on coronary blood flow velocity distal to coronary artery stenoses.

Despite the accepted clinical benefit of intra-aortic balloon counterpulsation (IABC), the physiologic explanation for its benefit remains controversial. Indirect methods of measuring coronary blood flow during IABC in obstructive coronary disease have yielded conflicting results. The direct measurement of coronary blood flow velocity distal to sites of stenoses by methods that do not potentially impede flow has not been previously reported. The aim of our study was to determine the effect of IABC on coronary blood flow velocity distal to a coronary stenosis by employing a method that would not impede flow through the stenosis. In an open-chest canine model, phasic and mean left anterior descending coronary artery flow velocities distal to varying degrees of stenosis were continuously measured by an epicardial Doppler probe with and without counterpulsation. All hemodynamic parameters were recorded in the absence of stenosis (n = 5) and the presence of subcritical (n = 5) and critical stenoses (n = 5). Heart rate was not affected by counterpulsation. Systolic blood pressure and rate-pressure product declined at all times with IABC. Compared to baseline, peak aortic diastolic pressure was augmented by an average of 24 mm Hg during IABC (p < 0.05). However, mean coronary artery flow velocities remained unchanged (101, 103 and 98% of baseline for no stenosis, subcritical stenosis and critical stenosis, respectively; p > 0.05 compared to baseline). Peak diastolic flow velocities were 106, 102 and 96% of baseline for no stenosis, subcritical and critical stenoses, respectively (p > 0.05). Despite the augmentation of peak diastolic pressure, distal coronary blood flow velocity was not increased by IABC in this canine model, irrespective of the severity of proximal coronary stenosis. These data suggest that augmentation of coronary artery flow distal to sites of stenoses is not primarily responsible for the clinical benefit observed when IABC is used in the setting of obstructive coronary artery disease. The reduction in afterload and myocardial oxygen demand observed in this model agrees with previous studies and likely accounts, at least in part, for the positive clinical results with IABC.

Coronary artery angioplasty with a helical autoperfusion balloon catheter

The initial in-hospital and long-term clinical experience with a helical autoperfusion balloon catheter in the treatment of coronary artery disease is reported. This new catheter design allows blood to flow passively around the inflated balloon through a protected helical channel molded into the balloon surface. Twelve consecutive patients underwent PTCA. Continuous ST monitoring, heart rate, average peak distal coronary blood flow velocity (APV), coronary blood flow (CBF), dP/dt and systemic and pulmonary arterial pressures were determined during PTCA. During balloon inflation there were no hemodynamic changes, TIMI flow was 1.7 +/- 0.8, and APV was 39% of baseline. Luminal diameter stenosis improved from 61 +/- 17 to 29 +/- 13% (P < 0.05) following PTCA. Mean continuous inflation duration was 385 +/- 215 sec and 6/12 patients had > or = 7.5-min inflations. There were no in-hospital adverse cardiac events. One patient developed recurrent angina during 8 mo of follow-up and underwent successful PTCA of a restenotic lesion. We conclude that human plaques can be successfully dilated with a helical balloon catheter that provides autoperfusion and the ability to perform prolonged inflations with hemodynamic stability. A comparison of this PTCA catheter with standard balloon catheters is warranted.

New concept in coronary angioplasty: Dilatation with a helical balloon that allows simultaneous autoperfusion

These preclinical studies investigate a new concept in coronary angioplasty and balloon catheter technology (the P100 catheter). The study sought to evaluate the morphology of experimental coronary arterial plaques dilated with the P100 in comparison to standard balloons, to determine the in vitro flow rates occurring during the inflation of the P100 in comparison to available perfusion catheters, and to assess the in vivo coronary flow velocity and the presence of ischemia during prolonged inflations with the P100. The development of myocardial ischemia is a major limitation of standard balloon angioplasty. To limit ischemia, autoperfusion catheters have been developed, in which blood flows through the balloon in the central catheter shaft. However, as the flow lumen profile is reduced to enhance the performance of these devices, so is the accompanying flow. An angioplasty catheter was designed to evaluate the feasibility of continuous autoperfusion around the dilatation balloon. The balloon surface was engineered to develop a helical trough for blood flow to occur during inflation. Arterial plaque morphology following angioplasty with the P100 (n = 8) and with standard balloons (n = 8) was evaluated in a swine model. In vitro flow rates during inflation of the P100 and available perfusion catheters were determined using 33% glycerol solution. In vivo coronary flow velocity was determined with a Doppler-tipped wire during 60-min continuous inflations with the P100, and 15-sec inflations with a standard balloon in 12 vessel segments in 7 dogs; using 3.0-3.5-mm-diameter balloons. All lesions were successfully dilated (< 50% luminal diameter stenosis) with the P100 and standard balloons. There were no morphologic differences in plaques dilated with P100 compared to standard balloons. In vitro flow rates with conventional 3.0-mm balloon perfusion catheters ranged from 27.1 +/- 2.1 ml/min (RX Flowtrack) to 38.7 +/- 0.9 ml/min (Stack Perfusion), P < .05. Flow with the P100 ranged from 54.8 +/- 4.3 ml/min (2.5-mm balloon) to 103.2 +/- 4.5 ml/min (3.5-mm balloon), P < .05. Distal average peak coronary flow velocity during prolonged P100 inflations varied from 69 +/- 7% of baseline at 5 min to 83 +/- 8% of baseline at 40 min, with an upward trend in velocity the longer the balloon was inflated. Hemodynamics remained stable. Experimental plaques are successfully dilated with a helical balloon by a mechanism that appears similar to the dilatation mechanism of standard balloons. These preclinical studies show that angioplasty and autoperfusion can be accomplished by a balloon that does not have complete surface area contact with the vessel wall. A gap created by the helix can thus provide a conduit for blood flow. Clinical studies will determine whether this innovation, which alters the tubular geometry of current angioplasty balloons, will provide autoperfusion and equivalent dilatation effects in human.

Successful identification and management of high-risk patients with acute myocardial infarction

The decision to use thrombolytic therapy in patients with acute myocardial infarction has been validated in recent large clinical trials. The identification of the high-risk patient, whether or not to use adjunctive strategies, and which patients may benefit from them are less clear. This article provides an overview of risk assessment for the patient with an acute myocardial infarction and the rationale for the use of certain clinical, electrocardiographic, and laboratory features in identifying patients at high risk. Also included is a discussion of the role of coronary angiography in the risk stratification of this patient population. Lastly, we explore the use of mechanical approaches to revascularization and suggest a t reatment strategy based on the severity of the patients coronary disease.

983-31 A New Coronary Artery Autoperfusion Dilatation Catheter

Standard coronary balloon angioplasty (SBA) is limited by the development of myocardial ischemia during balloon inflation. We describe a new autoperfusion dilatation catheter (GAP catheter) where blood flow occurs around the angioplasty balloon. Arterial morphology changes following GAP angioplasty were assessed in a swine atherosclerotic plaque model and compared to SBA (Nxa0=xa05). In order to assess coronary flow and the development of significant ischemia during GAP angioplasty, arterial pressure (BP). heart rate (HR), ECG and distal average peak coronary artery flow velocity(APV) (Doppler flow wire, Cardiometrics, Inc.) were determined in 7 dogs during 15 seconds of SBA and 60 minutes of continuous GAP angioplasty in 12 vessel segments, using 3.0–3.5 mm balloons, inflated to 6 atmospheres pressure. Distal flow dropped to zero during SBA in all animals. Results during GAP angioplasty are as follows: Minutes of Perfusion Angioplasty with GAP 5 10 20 40 60 HR * 103xa0±xa04 101xa0±xa05 103xa0±xa05 98xa0±xa05 100xa0±xa04 Systolic BP * 96xa0±xa07 97xa0±xa07 98xa0±xa07 103xa0±xa06 101xa0±xa06 APV * 69xa0±xa07 71xa0±xa08 76xa0±xa07 83xa0±xa08 76xa0±xa07 * data expressed as percent of baseline There were no arrhythmias during GAP angioplasty. Similar morphologic changes in the dilated plaque occurred following GAP and SBA. Conclusions Hemodynamic stability and maintenance of distal coronary flow velocity between 69% and 83% of baseline occur during a 60 minute inflation with a new autoperfusion angioplasty catheter. The absence of arrhythmias and stable hemodynamics suggest that significant ischemia during angioplasty is prevented with this new device. Histopathologic analysis following GAP angioplasty shows no differences compared to SBA. The GAP design can be adapted to any standard balloon catheter.