Ronak Delewi

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.

Prognostic Value of Microvascular Obstruction and Infarct Size, as Measured by CMR in STEMI Patients

The aim of this study was to evaluate the value of microvascular obstruction (MO) and infarct size as a percentage of left ventricular mass (IS%LV), as measured by contrast-enhanced cardiac magnetic resonance, in predicting major cardiovascular adverse events (MACE) at 2 years in patients with ST-segment elevation myocardial infarction reperfused by primary percutaneous coronary intervention. Individual data from 1,025 patients were entered into the pooled analysis. MO was associated with the occurrence of MACE, defined as a composite of cardiac death, congestive heart failure, and myocardial re-infarction (adjusted hazard ratio: 3.74; 95% confidence interval: 2.21 to 6.34). IS%LV ≥25% was not associated with MACE (adjusted hazard ratio: 0.90; 95% confidence interval: 0.59 to 1.37). The authors conclude that MO is an independent predictor of MACE and cardiac death, whereas IS%LV is not independently associated with MACE.

Impact of intracoronary bone marrow cell therapy on left ventricular function in the setting of ST-segment elevation myocardial infarction: a collaborative meta-analysis

AIMS The objective of the present analysis was to systematically examine the effect of intracoronary bone marrow cell (BMC) therapy on left ventricular (LV) function after ST-segment elevation myocardial infarction in various subgroups of patients by performing a collaborative meta-analysis of randomized controlled trials. METHODS AND RESULTS We identified all randomized controlled trials comparing intracoronary BMC infusion as treatment for ST-segment elevation myocardial infarction. We contacted the principal investigator for each participating trial to provide summary data with regard to different pre-specified subgroups [age, diabetes mellitus, time from symptoms to percutaneous coronary intervention, infarct-related artery, LV end-diastolic volume index (EDVI), LV ejection fraction (EF), infarct size, presence of microvascular obstruction, timing of cell infusion, and injected cell number] and three different endpoints [change in LVEF, LVEDVI, and LV end-systolic volume index (ESVI)]. Data from 16 studies were combined including 1641 patients (984 cell therapy, 657 controls). The absolute improvement in LVEF was greater among BMC-treated patients compared with controls: [2.55% increase, 95% confidence interval (CI) 1.83-3.26, P < 0.001]. Cell therapy significantly reduced LVEDVI and LVESVI (-3.17 mL/m², 95% CI: -4.86 to -1.47, P < 0.001; -2.60 mL/m², 95% CI -3.84 to -1.35, P < 0.001, respectively). Treatment benefit in terms of LVEF improvement was more pronounced in younger patients (age <55, 3.38%, 95% CI: 2.36-4.39) compared with older patients (age ≥ 55 years, 1.77%, 95% CI: 0.80-2.74, P = 0.03). This heterogeneity in treatment effect was also observed with respect to the reduction in LVEDVI and LVESVI. Moreover, patients with baseline LVEF <40% derived more benefit from intracoronary BMC therapy. LVEF improvement was 5.30%, 95% CI: 4.27-6.33 in patients with LVEF <40% compared with 1.45%, 95% CI: 0.60 to 2.31 in LVEF ≥ 40%, P < 0.001. No clear interaction was observed between other subgroups and outcomes. CONCLUSION Intracoronary BMC infusion is associated with improvement of LV function and remodelling in patients after ST-segment elevation myocardial infarction. Younger patients and patients with a more severely depressed LVEF at baseline derived most benefit from this adjunctive therapy.

Monocyte subset accumulation in the human heart following acute myocardial infarction and the role of the spleen as monocyte reservoir

AIMS Monocytes are critical mediators of healing following acute myocardial infarction (AMI), making them an interesting target to improve myocardial repair. The purpose of this study was a gain of insight into the source and recruitment of monocytes following AMI in humans. METHODS AND RESULTS Post-mortem tissue specimens of myocardium, spleen and bone marrow were collected from 28 patients who died at different time points after AMI. Twelve patients who died from other causes served as controls. The presence and localization of monocytes (CD14(+) cells), and their CD14(+)CD16(-) and CD14(+)CD16(+) subsets, were evaluated by immunohistochemical and immunofluorescence analyses. CD14(+) cells localized at distinct regions of the infarcted myocardium in different phases of healing following AMI. In the inflammatory phase after AMI, CD14(+) cells were predominantly located in the infarct border zone, adjacent to cardiomyocytes, and consisted for 85% (78-92%) of CD14(+)CD16(-) cells. In contrast, in the subsequent post-AMI proliferative phase, massive accumulation of CD14(+) cells was observed in the infarct core, containing comparable proportions of both the CD14(+)CD16(-) [60% (31-67%)] and CD14(+)CD16(+) subsets [40% (33-69%)]. Importantly, in AMI patients, of the number of CD14(+) cells was decreased by 39% in the bone marrow and by 58% in the spleen, in comparison with control patients (P = 0.02 and <0.001, respectively). CONCLUSIONS Overall, this study showed a unique spatiotemporal pattern of monocyte accumulation in the human myocardium following AMI that coincides with a marked depletion of monocytes from the spleen, suggesting that the human spleen contains an important reservoir function for monocytes.

Left ventricular thrombus formation after acute myocardial infarction

Cardiovascular disease remains the leading cause of death in western society. Mortality from acute myocardial infarction (AMI) has decreased since the introduction of primary percutaneous coronary intervention (PCI), which has proved to be superior to thrombolytic therapy by demonstrating lower mortality rates and reduced clinical adverse events. Nevertheless, postinfarct complications still lead to morbidity and mortality in a large number of patients. One of the most feared complications is the occurrence of thromboembolic events (mostly cerebrovascular accidents) due to left ventricular (LV) thrombus formation. The risk of LV thrombus formation is highest during the first 3 months following acute myocardial infarction, but the potential for cerebral emboli persists in the large population of patients with chronic LV dysfunction. Since these thromboembolic events are usually unheralded by warning signs of transient cerebral ischaemia, the only truly satisfactory medical approach is adequate management of these high risk groups. This article discusses the incidence, diagnosis and management of LV thrombus formation after an AMI. The combination of blood stasis, endothelial injury and hypercoagulability, often referred to as Virchows triad, is a prerequisite for in vivo thrombus formation. In the presence of LV thrombus formation after AMI, the three components of this triad can also be recognised (figure 1). LV regional wall akinesia and dyskinesia result in blood stasis, often recognised on two dimensional echocardiography by the occurrence of spontaneous LV contrast. Prolonged ischaemia leads to subendocardial tissue injury with inflammatory changes. Finally, patients with an acute coronary syndrome display a hypercoagulable state with, for example, increased concentrations of prothrombin, fibrinopeptide A, and von Willebrand factor, and decreased concentrations of the enzyme responsible for cleaving von Willebrand factor (ADAMTS13).w1 w2 This triad can result in the formation of LV thrombus composed …

Diagnostic Accuracy of Combined Intracoronary Pressure and Flow Velocity Information During Baseline Conditions Adenosine-Free Assessment of Functional Coronary Lesion Severity

Background— The assessment of functional coronary lesion severity using intracoronary physiological parameters such as coronary flow velocity reserve and the more widely used fractional flow reserve relies critically on the establishment of maximal hyperemia. We evaluated the diagnostic accuracy of the stenosis resistance index during nonhyperemic conditions, baseline stenosis resistance index, compared with established hyperemic intracoronary hemodynamic parameters, because achievement of hyperemia can be cumbersome in daily clinical practice. Methods and Results— A total of 228 patients, including 299 lesions (mean stenosis diameter 55%±11%), underwent myocardial perfusion scintigraphy for documentation of reversible perfusion defects. Distal coronary pressure and flow velocity were assessed with sensor-equipped guidewires during baseline and maximal hyperemia, induced by an intracoronary bolus of adenosine (20–40 µg). We determined stenosis resistance (SR) during baseline and hyperemic conditions as well as fractional flow reserve and coronary flow velocity reserve. The discriminative value for myocardial ischemia on myocardial perfusion scintigraphy of all parameters was compared using receiver-operating-characteristic curves. Baseline SR showed good agreement with myocardial perfusion scintigraphy. The diagnostic performance of baseline SR (area under the curve, 0.77; 95% CI, 0.71–0.83) was as accurate as fractional flow reserve and coronary flow velocity reserve (area under the curve, 0.77; 95% CI, 0.71–0.83 and area under the curve, 0.75; 95% CI, 0.68–0.81 respectively; P>0.05 compared with baseline SR for both). However, hyperemic SR, combining both pressure and flow velocity information during hyperemia, was superior to all other parameters (area under the curve, 0.81; 95% CI, 0.76–0.87; P<0.05 compared with all other parameters). Conclusions— Combined pressure and flow velocity measurements during baseline conditions may provide a useful tool for functional lesion severity assessment without the need for potent vasodilators.

Impact of intracoronary cell therapy on left ventricular function in the setting of acute myocardial infarction: a meta-analysis of randomised controlled clinical trials

Context Numerous randomized controlled studies assessing intracoronary bone marrow cell therapy (BMC) after acute myocardial infarction (AMI) have been performed. Objective To systematically review the effect of autologous BMC therapy on left ventricular function by performing an up to date meta-analysis of randomized controlled trials (RCTs) including long-term follow-up. Data sources Trials were indentified through a literature search from 1980 to June 2012 of the Pubmed, Embase, Cochrane database, and the Current Controlled Trials Register. Study selection Randomized clinical trials comparing intracoronary BMC infusion to control as treatment for AMI. Data extraction The primary endpoint was the change in left ventricular ejection fraction (LVEF) from baseline to follow-up. Secondary endpoints were changes in left ventricular end diastolic volume (LVEDV), left ventricular end systolic volume (LVESV), infarct size and clinical outcomes. Results Improvement of LVEF in patients receiving intracoronary BMC was significantly better within 6 months (23 studies, 2.23% (95% confidence interval (CI) 1.00 to 3.47); p<0.001). At 12 months of follow-up, this effect sustained with 3.91% more LVEF improvement (11 studies, (95% CI 2.56 to 5.27), p<0.001). At long-term follow-up, we found a trend for better LVEF improvement in favor of cell therapy (7 studies, 1.90% (95% CI −0.43 to 4.23); p=0.11). There was no clear effect in infarct size or LVEDV. However, we found a significant reduction in LVESV at 6 months (−4.81 ml (95% CI −7.86 to −1.76); p<0.001 and at 12 months (−9.41 ml (95% CI −13.64 to −5.17); p<0.001). Moreover, there was a statistically significant decrease in recurrent AMI (Relative Risk (RR) 0.44 (95% CI 0.24 to 0.79); p=0.007), and readmission for heart failure, unstable angina or chest pain (RR 0.59 (95% CI 0.35 to 0.98); p=0.04) in favour of cell therapy. Conclusion Intracoronary BMC treatment leads to a moderate improvement of LVEF and reduction of LVESV at 6 months that sustained at 12 months follow-up, without a clear significant effect on LVEDV, or infarct size. Furthermore, we found that intracoronary cell therapy is significantly associated with a reduction in recurrent AMI and readmission for heart failure, unstable angina or chest pain.

A proinflammatory monocyte response is associated with myocardial injury and impaired functional outcome in patients with ST-segment elevation myocardial infarction: Monocytes and myocardial infarction

BACKGROUND In patients with ST-segment elevation myocardial infarction (STEMI), the importance of a well-balanced inflammatory reaction has been recognized for years. Monocytes play essential roles in regulating inflammation. Hence, we investigated the association between inflammatory characteristics of monocytes and myocardial injury and functional outcome in patients with STEMI. METHODS Using flow cytometry, the levels of classical (CD14(++)CD62L(+)) and nonclassical (CD14(+)CD62L(-)) monocytes were analyzed in peripheral blood in 58 patients with STEMI at a median of 5 days (4-6 days) after primary percutaneous coronary intervention. In addition, the monocytic expression of several surface molecules and formation of monocyte-platelet complexes were measured. All patients underwent cardiovascular magnetic resonance imaging at baseline and 4-month follow-up. RESULTS At baseline, patients with high levels of classical monocytes had impaired left ventricular (LV) ejection fraction (P = .002), larger infarct size (P = .001), and, often, presence of microvascular obstruction (P = .003). At follow-up, high levels of classical monocytes were negatively associated with the regional systolic LV function independent of the transmural extent of infarction. In contrast, positive associations for the levels of nonclassical monocytes were observed. Finally, up-regulation of macrophage 1 by blood monocytes and increased formation of monocyte-platelet complexes were associated with enhanced myocardial injury at baseline and impaired LV function at follow-up. CONCLUSIONS This study shows an association between a proinflammatory monocyte response, characterized by high levels of classical monocytes, and severe myocardial injury and poor functional outcome after STEMI. Future studies are required to investigate the biologic nature of this association and therapeutic implications.

Impact of Coronary Microvascular Function on Long-Term Cardiac Mortality in Patients With Acute ST-Segment–Elevation Myocardial Infarction

Background—Microvascular function is increasingly being recognized as an important marker of risk in coronary artery disease, and may be accurately assessed by intracoronary Doppler flow velocity measurements. In the setting of ST-segment–elevation myocardial infarction there are limited data regarding the prognostic value of microvascular function in both infarct-related and reference coronary arteries for long-term clinical outcome. We sought to determine the prognostic value of microvascular function, as assessed by Doppler flow velocity measurements, for cardiac mortality after primary percutaneous coronary intervention for acute ST-segment–elevation myocardial infarction. Methods and Results—Between April 1997 and August 2000, we included 100 consecutive patients with a first anterior wall ST-segment–elevation myocardial infarction. Immediately after primary percutaneous coronary intervention, intracoronary Doppler flow velocity was measured in the infarct-related artery, to determine coronary flow velocity reserve (CFVR), diastolic deceleration time, and the presence of systolic retrograde flow, as well as in a reference vessel to determine reference vessel CFVR. The primary end point was cardiac mortality at 10-year follow-up. Complete follow-up was obtained in 94 patients (94%). At 10-year follow-up, cardiac mortality amounted to 14%. Cardiac mortality amounted to 5% when reference vessel CFVR was normal (≥2.1), in contrast to 31% when abnormal (<2.1; P=0.001). Reference vessel CFVR <2.1 was associated with a 4.09 increase in long-term cardiac mortality hazard after multivariate adjustment for identified predictors for cardiac mortality (hazard ratio, 4.09; 95% confidence interval, 1.18–14.17; P=0.03) Conclusions—Microvascular dysfunction, measured by reference vessel CFVR determined after primary percutaneous coronary intervention for acute anterior wall ST-segment–elevation myocardial infarction is associated with a significantly increased long-term cardiac mortality.

Antiplatelet therapy following transcatheter aortic valve implantation

Objective There is limited evidence to support decision making on antiplatelet therapy following transcatheter aortic valve implantation (TAVI). Our aim was to assess the efficacy and safety of aspirin-only (ASA) versus dual antiplatelet therapy (DAPT) following TAVI. Methods We performed a systematic review and pooled analysis of individual patient data from 672 participants comparing single versus DAPT following TAVI. Primary endpoint was defined as the composite of net adverse clinical and cerebral events (NACE) at 1 month, including all-cause mortality, acute coronary syndrome (ACS), stroke, life-threatening and major bleeding. Results At 30 days a NACE rate of 13% was observed in the ASA-only and in 15% of the DAPT group (OR 0.83, 95% CI 0.48 to 1.43, p=0.50). A tendency towards less life-threatening and major bleeding was observed in patients treated with ASA (OR 0.56, 95% CI 0.28 to 1.11, p=0.09). Also, ASA was not associated with an increased all-cause mortality (OR 0.91, 95% CI 0.36 to 2.27, p=0.83), ACS (OR 0.5, 95% CI 0.05 to 5.51, p=0.57) or stroke (OR 1.21; 95% CI 0.36 to 4.03, p=0.75). Conclusions No difference in 30-day NACE rate was observed between ASA-only or DAPT following TAVI. Moreover, a trend towards less life-threatening and major bleeding was observed in favour of ASA. Consequently the additive value of clopidogrel warrants further investigation.