Robbert J. de Winter

A systematic review and meta-analysis of intra-aortic balloon pump therapy in ST-elevation myocardial infarction : should we change the guidelines?

Aims Intra-aortic balloon counterpulsation (IABP) in ST-segment elevation myocardial infarction (STEMI) with cardiogenic shock is strongly recommended (class IB) in the current guidelines. We performed meta-analyses to evaluate the evidence for IABP in STEMI with and without cardiogenic shock. Methods and results Medical literature databases were scrutinized to identify randomized trials comparing IABP with no IABP in STEMI. In absence of randomized trials, cohort studies of IABP in STEMI with cardiogenic shock were identified. Two separate meta-analyses were performed respectively. The first meta-analysis included seven randomized trials (n = 1009) of STEMI. IABP showed neither a 30-day survival benefit nor improved left ventricular ejection fraction, while being associated with significantly higher stroke and bleeding rates. The second meta-analysis included nine cohorts of STEMI patients with cardiogenic shock (n = 10529). In patients treated with thrombolysis, IABP was associated with an 18% [95% confidence interval (CI), 16-20%; P < 0.0001] decrease in 30 day mortality, albeit with significantly higher revascularization rates compared to patients without support. Contrariwise, in patients treated with primary percutaneous coronary intervention, IABP was associated with a 6% (95% CI, 3-10%; P < 0.0008) increase in 30 day mortality. Conclusion The pooled randomized data do not support IABP in patients with high-risk STEMI. The meta-analysis of cohort studies in the setting of STEMI complicated by cardiogenic shock supported IABP therapy adjunctive to thrombolysis. In contrast, the observational data did not support IABP therapy adjunctive to primary PCI. All available observational data concerning IABP therapy in the setting of cardiogenic shock is importantly hampered by bias and confounding. There is insufficient evidence endorsing the current guideline recommendation for the use of IABP therapy in the setting of STEMI complicated by cardiogenic shock. Our meta-analyses challenge the current guideline recommendations.

Long-Term Outcome of a Routine Versus Selective Invasive Strategy in Patients With Non-ST-Segment Elevation Acute Coronary Syndrome: A Meta-Analysis of Individual Patient Data

OBJECTIVES This study was designed to determine: 1) whether a routine invasive (RI) strategy reduces the long-term frequency of cardiovascular death or nonfatal myocardial infarction (MI) using a meta-analysis of individual patient data from all randomized studies with 5-year outcomes; and 2) whether the results are influenced by baseline risk. BACKGROUND Pooled analyses of randomized trials show early benefit of routine intervention, but long-term results are inconsistent. The differences may reflect differing trial design, adjunctive therapies, and/or limited power. This meta-analysis (n = 5,467 patients) is designed to determine whether outcomes are improved despite trial differences. METHODS Individual patient data, with 5-year outcomes, were obtained from FRISC-II (Fragmin and Fast Revascularization during Instability in Coronary Artery Disease), ICTUS (Invasive Versus Conservative Treatment in Unstable Coronary Syndromes), and RITA-3 (Randomized Trial of a Conservative Treatment Strategy Versus an Interventional Treatment Strategy in Patients with Unstable Angina) trials for a collaborative meta-analysis. A Cox regression analysis was used for a multivariable risk model, and a simplified integer model was derived. RESULTS Over 5 years, 14.7% (389 of 2,721) of patients randomized to an RI strategy experienced cardiovascular death or nonfatal MI versus 17.9% (475 of 2,746) in the selective invasive (SI) strategy (hazard ratio [HR]: 0.81, 95% confidence interval [CI]: 0.71 to 0.93; p = 0.002). The most marked treatment effect was on MI (10.0% RI strategy vs. 12.9% SI strategy), and there were consistent trends for cardiovascular deaths (HR: 0.83, 95% CI: 0.68 to 1.01; p = 0.068) and all deaths (HR: 0.90, 95% CI: 0.77 to 1.05). There were 2.0% to 3.8% absolute reductions in cardiovascular death or MI in the low- and intermediate-risk groups and an 11.1% absolute risk reduction in highest-risk patients. CONCLUSIONS An RI strategy reduces long-term rates of cardiovascular death or MI and the largest absolute effect in seen in higher-risk patients.

Darapladib for Preventing Ischemic Events in Stable Coronary Heart Disease

BACKGROUND Elevated lipoprotein-associated phospholipase A2 activity promotes the development of vulnerable atherosclerotic plaques, and elevated plasma levels of this enzyme are associated with an increased risk of coronary events. Darapladib is a selective oral inhibitor of lipoprotein-associated phospholipase A2. METHODS In a double-blind trial, we randomly assigned 15,828 patients with stable coronary heart disease to receive either once-daily darapladib (at a dose of 160 mg) or placebo. The primary end point was a composite of cardiovascular death, myocardial infarction, or stroke. Secondary end points included the components of the primary end point as well as major coronary events (death from coronary heart disease, myocardial infarction, or urgent coronary revascularization for myocardial ischemia) and total coronary events (death from coronary heart disease, myocardial infarction, hospitalization for unstable angina, or any coronary revascularization). RESULTS During a median follow-up period of 3.7 years, the primary end point occurred in 769 of 7924 patients (9.7%) in the darapladib group and 819 of 7904 patients (10.4%) in the placebo group (hazard ratio in the darapladib group, 0.94; 95% confidence interval [CI], 0.85 to 1.03; P=0.20). There were also no significant between-group differences in the rates of the individual components of the primary end point or in all-cause mortality. Darapladib, as compared with placebo, reduced the rate of major coronary events (9.3% vs. 10.3%; hazard ratio, 0.90; 95% CI, 0.82 to 1.00; P=0.045) and total coronary events (14.6% vs. 16.1%; hazard ratio, 0.91; 95% CI, 0.84 to 0.98; P=0.02). CONCLUSIONS In patients with stable coronary heart disease, darapladib did not significantly reduce the risk of the primary composite end point of cardiovascular death, myocardial infarction, or stroke. (Funded by GlaxoSmithKline; STABILITY ClinicalTrials.gov number, NCT00799903.).

Value of Myoglobin, Troponin T, and CK-MBmass in Ruling Out an Acute Myocardial Infarction in the Emergency Room

BACKGROUND Ruling out acute myocardial infarction (AMI) on the basis of rapid assays for cardiac markers will allow early triage of patients and cost-effective use of available coronary care facilities. METHODS AND RESULTS We studied the value of myoglobin, creatine kinase (CK)-MBmass, and troponin T in ruling out an AMI in the emergency room in 309 consecutive patients presenting with chest pain. The gold standard for AMI was the combination of history, ECG, and a typical curve of the CK-MB activity (CK-MBact). Myoglobin was the earliest marker, and its negative predictive value (NPV) was significantly higher than for CK-MBmass and troponin T from 3 to 6 hours after the onset of symptoms (myoglobin versus CK-MBmass, P < .03; myoglobin versus troponin T, P < .01). The NPV of myoglobin reached 89% 4 hours after the onset of symptoms. The NPV of CK-MBmass reached 95% 7 hours after the onset of symptoms. Troponin T was not an early marker for ruling out AMI, and NPV changed over time, together with CK-MBact. The early NPV was higher in a subgroup of patients with a low probability of the presence of AMI for the three markers. Cardiac markers rise earlier in patients with large infarcts than in patients with small infarcts as indicated by the cumulative proportion of the marker above the upper reference limit at each time point (myoglobin, P = .04; CK-MBmass, P = .013; troponin T, P = .016). CONCLUSIONS For ruling out AMI in the emergency room, myoglobin is a better marker than CK-MBmass or troponin T from 3 until 6 hours after the onset of symptoms, but the maximal NPV reaches only 89%. At 7 hours, the NPV of CK-MBmass is 95%. The test characteristics are influenced by the probability of the presence of AMI in the patients studied and by the size of their AMI. Infarct size of AMI patients should be reported in studies evaluating cardiac markers.

Plaque Instability Frequently Occurs Days or Weeks Before Occlusive Coronary Thrombosis A Pathological Thrombectomy Study in Primary Percutaneous Coronary Intervention

Background—Acute ST-elevation myocardial infarction (STEMI) is caused by sudden occlusive coronary thrombosis, after plaque disruption; however, a considerable time interval between plaque disturbance and the onset of symptoms has been suggested. We therefore studied the age of intracoronary thrombi, aspirated during angioplasty in patients with acute STEMI. Methods and Results—Percutaneous intracoronary thrombectomy during angioplasty was performed in 211 consecutive STEMI patients within 6 hours after onset of anginal symptoms. The aspirated material was histologically screened on thrombus and plaque components, and thrombus age was classified as fresh (<1 day), lytic thrombus (1 to 5 days), and organized thrombus (>5 days). In all patients, intracoronary-derived material was retrieved in the filter of the collection bottle. Thrombus was identified in 199 (95%) of 211 patients. In 12 patients (5%), only plaque components were identified, and in 85 patients (41%), both thrombus and plaque material were aspirated. In 18 (9%) of 199 patients, the thrombus was organized, and in 70 patients (35%), the thrombus showed lytic changes, whereas in 98 (49%), a completely fresh thrombus was found. In 14 (7%) of 199 patients, the thrombus showed combined features of both fresh thrombus and organized thrombus. Conclusions—In at least 50% of patients with acute STEMI, coronary thrombi were days or weeks old. This indicates that sudden coronary occlusion is often preceded by a variable period of plaque instability and thrombus formation, initiated days or weeks before onset of symptoms.

Role of variability in microvascular resistance on fractional flow reserve and coronary blood flow velocity reserve in intermediate coronary lesions

BackgroundFractional flow reserve (FFR) and coronary blood flow velocity reserve (CFR) represent physiological quantities used to evaluate coronary lesion severity and to make clinical decisions. A comparison between the outcomes of both diagnostic techniques has not been performed in a large cohort of patients with intermediate coronary lesions. Methods and ResultsFFR and CFR were assessed in 126 consecutive patients with 150 intermediate coronary lesions (between 40% and 70% diameter stenosis by visual assessment). Agreement between outcomes of FFR and CFR, categorized at cut-off values of 0.75 and 2.0, respectively, was observed in 109 coronary lesions (73%), whereas discordant outcomes were present in 41 lesions (27%). In 26 of these 41 lesions, FFR was <0.75 and CFR≥2.0 (group A); in the remaining 15 lesions, FFR was ≥0.75 and CFR<2.0 (group B). Minimum microvascular resistance, defined as the ratio of mean distal pressure to average peak blood flow velocity during maximum hyperemia, showed a large variability (overall range, 0.65 to 4.64 mm Hg · cm−1 · s−1) and was significantly higher in group B than in group A (2.42±0.77 versus 1.91±0.70 mm Hg · cm−1 · s−1;P =0.034). ConclusionsOur findings demonstrate the prominent role of microvascular resistance in modulating the relationship between FFR and CFR and emphasize the importance of combined pressure and flow velocity measurements to evaluate coronary lesion severity and microvascular involvement.

Single-Wire Pressure and Flow Velocity Measurement to Quantify Coronary Stenosis Hemodynamics and Effects of Percutaneous Interventions

Background—Lack of high-fidelity simultaneous measurements of pressure and flow velocity distal to a coronary artery stenosis has hampered the study of stenosis pressure drop–velocity (&Dgr;P-v) relationships in patients. Methods and Results—A novel 0.014-inch dual-sensor (pressure and Doppler velocity) guidewire was used in 15 coronary lesions to obtain per-beat averages of pressure drop and velocity after an intracoronary bolus of adenosine. &Dgr;P-v relations from resting to maximal hyperemic velocity were constructed before and after stepwise executed percutaneous coronary intervention (PCI). Before PCI, half of the &Dgr;P-v relations revealed the presence of a compliant stenosis, which was stabilized by angioplasty. Fractional flow reserve (FFR), coronary flow reserve (CFVR), and velocity-based indices of stenosis resistance (h-SRv) and microvascular resistance (h-MRv) at maximal hyperemia were compared. Stepwise PCI significantly lowered h-SRv, with an initial marked reduction in hyperemic pressure drop followed by further gains in velocity. A concomitant significant reduction of h-MRv accounted for half of the gain in velocity after PCI. The average magnitude of absolute incremental hemodynamic changes was highest for h-SRv (56.8±39.2%) compared with CFVR (35.3±34.5%, P <0.005) or FFR (19.5±25.2%, P <0.0001). Conclusions—&Dgr;P-v relations comprehensively visualize improvements in coronary hemodynamics after PCI. h-SRv is a powerful and sensitive descriptor of the functional gain achieved by PCI, combining information about both pressure gradient and velocity, which are oppositely affected by PCI. Simultaneous assessment of stenosis and microvascular resistance may provide a valuable tool for guidance of PCI.

Physiological Basis and Long-Term Clinical Outcome of Discordance Between Fractional Flow Reserve and Coronary Flow Velocity Reserve in Coronary Stenoses of Intermediate Severity

Background—Discordance between fractional flow reserve (FFR) and coronary flow velocity reserve (CFVR) may reflect important coronary pathophysiology but usually remains unnoticed in clinical practice. We evaluated the physiological basis and clinical outcome associated with FFR/CFVR discordance. Methods and Results—We studied 157 intermediate coronary stenoses in 157 patients, evaluated by FFR and CFVR between April 1997 and September 2006 in which revascularization was deferred. Long-term follow-up was performed to document the occurrence of major adverse cardiac events: cardiac death, myocardial infarction, or target vessel revascularization. Discordance between FFR and CFVR occurred in 31% and 37% of stenoses at the 0.75, and 0.80 FFR cut-off value, respectively, and was characterized by microvascular resistances during basal and hyperemic conditions. Follow-up duration amounted to 11.7 years (Q1–Q3, 9.9–13.3 years). Compared with concordant normal results of FFR and CFVR, a normal FFR with an abnormal CFVR was associated with significantly increased major adverse cardiac events rate throughout 10 years of follow-up, regardless of the FFR cut-off applied. In contrast, an abnormal FFR with a normal CFVR was associated with equivalent clinical outcome compared with concordant normal results: ⩽3 years when FFR <0.75 was depicted abnormal and throughout 10 years of follow-up when FFR ⩽0.80 was depicted abnormal. Conclusions—Discordance of CFVR with FFR originates from the involvement of the coronary microvasculature. Importantly, the risk for major adverse cardiac events associated with FFR/CFVR discordance is mainly attributable to stenoses where CFVR is abnormal. This emphasizes the requirement of intracoronary flow assessment in addition to coronary pressure for optimal risk stratification in stable coronary artery disease.

Hyperemic Stenosis Resistance Index for Evaluation of Functional Coronary Lesion Severity

Background—Both coronary blood flow velocity reserve (CFVR) and myocardial fractional flow reserve (FFR) are used to evaluate the hemodynamic severity of coronary lesions. However, discordant results between CFVR and FFR have been observed in 25% to 30% of intermediate coronary lesions. An index of stenosis resistance based on a combination of intracoronary pressure and flow velocity may improve the assessment of functional coronary lesion severity. Methods and Results—Single photon emission computed tomography (SPECT) was performed in 151 patients with angina to determine reversible perfusion defects within one-week before cardiac catheterization. Coronary pressure and flow velocity was measured distal to 181 single coronary lesions with a mean diameter stenosis of 56% (range: 32% to 85%). Maximum hyperemia was induced by 15 to 20 &mgr;g IC adenosine to determine CFVR, FFR, and the hyperemic stenosis resistance index (h-SRv), defined as the ratio of hyperemic stenosis pressure gradient (mean aorta pressure-mean distal pressure) and hyperemic average peak-flow velocity. Receiver-operating-characteristic curves of CFVR, FFR, and h-SRv were calculated to evaluate the predictive value for presence of reversible perfusion defects on SPECT with the use of the area under curve (AUC). The AUC was significantly higher for h-SRv (0.90±0.03) compared with those for CFVR (0.80±0.04;P =0.024) and FFR (0.82±0.03;P =0.018), respectively. Agreement with SPECT was particularly higher (73%) than for CFVR (49%, P =0.022) or FFR (51%, P =0.037) in the group of lesions showing discordant results between CFVR and FFR Conclusion—These results indicate that hyperemic stenosis resistance index is a more powerful predictor of reversible perfusion defects than CFVR or FFR.

Relationship of Thrombus Healing to Underlying Plaque Morphology in Sudden Coronary Death

OBJECTIVES The aim of this study was to assess differences in thrombus healing between ruptured and eroded plaques, given the natural difference in lesion substrate and that thrombi might exist days to weeks before the presentation of sudden coronary death. BACKGROUND Although the ability to distinguish ruptures and erosions remains a major clinical challenge, in-hospital patients dying with acute myocardial infarction establish that erosions account for 25% of all deaths, where women experience a higher incidence compared with men. METHODS Coronary lesions with thrombi (ruptures, n = 65; erosions, n = 50) received in consultation from the Medical Examiners Office from 111 sudden death victims were studied. Thrombus healing was classified as early (<1 day) or late stage characterized in phases of lytic (1 to 3 days), infiltrating (4 to 7 days), or healing (>7 days). Morphometric analysis included vessel dimensions, necrotic core size, and macrophage density. RESULTS Late-stage thrombi were identified in 79 of 115 (69%) culprit plaques. Women more frequently had erosion with a greater prevalence of late-stage thrombi (44 of 50, 88%) than ruptures (35 of 65, 54%, p < 0.0001). The internal elastic lamina area and percent stenosis were significantly smaller in erosions compared with ruptures (p < 0.0001 and p = 0.02), where plaque burden was greater (p = 0.008). Although macrophage infiltration in erosions was significantly less than ruptures (p = 0.03), there was no established relationship with thrombus organization. Other parameters of thrombus length and occlusive versus nonocclusive showed no association with healing. CONCLUSIONS Approximately two-thirds of coronary thrombi in sudden coronary deaths are organizing, particularly in young individuals-especially women, who perhaps might require a different strategy of treatment.