Alex Sirker

Baseline Bleeding Risk and Arterial Access Site Practice in Relation to Procedural Outcomes After Percutaneous Coronary Intervention

BACKGROUND Transradial access (TRA) has been associated with reduced access site-related bleeding complications and mortality after percutaneous coronary intervention (PCI). It is unclear, however, whether these observed benefits are influenced by baseline bleeding risk. OBJECTIVES This study investigated the relationship between baseline bleeding risk, TRA utilization, and procedure-related outcomes in patients undergoing PCI enrolled in the British Cardiovascular Intervention Society database. METHODS Baseline bleeding risk was calculated by using modified Mehran bleeding risk scores in 348,689 PCI procedures performed between 2006 and 2011. Four categories for bleeding risk were defined for the modified Mehran risk score (MMRS): low (<10), moderate (10 to 14), high (15 to 19), and very high (≥20). The impact of baseline bleeding risk on 30-day mortality and its relationship with access site were studied. RESULTS TRA was independently associated with a 35% reduction in 30-day mortality risk (odds ratio [OR]: 0.65 [95% confidence interval (CI): 0.59 to 0.72]; p < 0.0001), with the magnitude of mortality reduction related to baseline bleeding risk (MMRS <10, OR: 0.73 [95% CI: 0.62 to 0.86]; MMRS ≥20, OR: 0.53 [95% CI: 0.47 to 0.61]). In patients with an MMRS <10, TRA was used in 71,771 (43.2%) of 166,083 PCI procedures; TRA was used in 8,655 (40.1%) of 21,559 PCI procedures in patients with an MMRS ≥20, illustrating that TRA was used less in those at highest risk from bleeding complications (p < 0.0001). CONCLUSIONS TRA was independently associated with reduced 30-day mortality, and the magnitude of this effect was related to baseline bleeding risk; those at highest risk of bleeding complications gained the greatest benefit from adoption of TRA during PCI.

Residual Myocardial Iron Following Intramyocardial Hemorrhage During the Convalescent Phase of Reperfused ST-Segment–Elevation Myocardial Infarction and Adverse Left Ventricular Remodeling

Background—The presence of intramyocardial hemorrhage (IMH) in ST-segment–elevation myocardial infarction patients reperfused by primary percutaneous coronary intervention has been associated with residual myocardial iron at follow-up, and its impact on adverse left ventricular (LV) remodeling is incompletely understood and is investigated here. Methods and Results—Forty-eight ST-segment–elevation myocardial infarction patients underwent cardiovascular magnetic resonance at 4±2 days post primary percutaneous coronary intervention, of whom 40 had a follow-up scan at 5±2 months. Native T1, T2, and T2* maps were acquired. Eight out of 40 (20%) patients developed adverse LV remodeling. A subset of 28 patients had matching T2* maps, of which 15/28 patients (54%) had IMH. Eighteen of 28 (64%) patients had microvascular obstruction on the acute scan, of whom 15/18 (83%) patients had microvascular obstruction with IMH. On the follow-up scan, 13/15 patients (87%) had evidence of residual iron within the infarct zone. Patients with residual iron had higher T2 in the infarct zone surrounding the residual iron when compared with those without. In patients with adverse LV remodeling, T2 in the infarct zone surrounding the residual iron was also higher than in those without (60 [54–64] ms versus 53 [51–56] ms; P=0.025). Acute myocardial infarct size, extent of microvascular obstruction, and IMH correlated with the change in LV end-diastolic volume (Pearson’s rho of 0.64, 0.59, and 0.66, respectively; P=0.18 and 0.62, respectively, for correlation coefficient comparison) and performed equally well on receiver operating characteristic curve for predicting adverse LV remodeling (area under the curve: 0.99, 0.94, and 0.95, respectively; P=0.19 for receiver operating characteristic curve comparison). Conclusions—The majority of ST-segment–elevation myocardial infarction patients with IMH had residual myocardial iron at follow-up. This was associated with persistently elevated T2 values in the surrounding infarct tissue and adverse LV remodeling. IMH and residual myocardial iron may be potential therapeutic targets for preventing adverse LV remodeling in reperfused ST-segment–elevation myocardial infarction patients.

Quantifying the Area at Risk in Reperfused ST-Segment–Elevation Myocardial Infarction Patients Using Hybrid Cardiac Positron Emission Tomography–Magnetic Resonance Imaging

Background—Hybrid positron emission tomography and magnetic resonance allows the advantages of magnetic resonance in tissue characterizing the myocardium to be combined with the unique metabolic insights of positron emission tomography. We hypothesized that the area of reduced myocardial glucose uptake would closely match the area at risk delineated by T2 mapping in ST-segment–elevation myocardial infarction patients. Methods and Results—Hybrid positron emission tomography and magnetic resonance using 18F-fluorodeoxyglucose (FDG) for glucose uptake was performed in 21 ST-segment–elevation myocardial infarction patients at a median of 5 days. Follow-up scans were performed in a subset of patients 12 months later. The area of reduced FDG uptake was significantly larger than the infarct size quantified by late gadolinium enhancement (37.2±11.6% versus 22.3±11.7%; P<0.001) and closely matched the area at risk by T2 mapping (37.2±11.6% versus 36.3±12.2%; P=0.10, R=0.98, bias 0.9±4.4%). On the follow-up scans, the area of reduced FDG uptake was significantly smaller in size when compared with the acute scans (19.5 [6.3%–31.8%] versus 44.0 [21.3%–55.3%]; P=0.002) and closely correlated with the areas of late gadolinium enhancement (R 0.98) with a small bias of 2.0±5.6%. An FDG uptake of ≥45% on the acute scans could predict viable myocardium on the follow-up scan. Both transmural extent of late gadolinium enhancement and FDG uptake on the acute scan performed equally well to predict segmental wall motion recovery. Conclusions—Hybrid positron emission tomography and magnetic resonance in the reperfused ST-segment–elevation myocardial infarction patients showed reduced myocardial glucose uptake within the area at risk and closely matched the area at risk delineated by T2 mapping. FDG uptake, as well as transmural extent of late gadolinium enhancement, acutely can identify viable myocardial segments.Background Hybrid Positron Emission Tomography and Magnetic Resonance (PET-MR) allows the advantages of MR in tissue characterizing the myocardium to be combined with the unique metabolic insights of PET. We hypothesized that the area of reduced myocardial glucose uptake would closely match the area-at-risk (AAR) delineated by T2-mapping in ST-segment elevation myocardial infarction (STEMI) patients.

Clinical benefit of adenosine as an adjunct to reperfusion in ST-elevation myocardial infarction patients: An updated meta-analysis of randomized controlled trials.

Background Adenosine administered as an adjunct to reperfusion can reduce coronary no-reflow and limit myocardial infarct (MI) size in ST-segment elevation myocardial infarction (STEMI) patients. Whether adjunctive adenosine therapy can improve clinical outcomes in reperfused STEMI patients is not clear and is investigated in this meta-analysis of 13 randomized controlled trials (RCTs). Methods We performed an up-to-date search for all RCTs investigating adenosine as an adjunct to reperfusion in STEMI patients. We calculated pooled relative risks using a fixed-effect meta-analysis assessing the impact of adjunctive adenosine therapy on major clinical endpoint including all-cause mortality, non-fatal myocardial infarction, and heart failure. Surrogate markers of reperfusion were also analyzed. Results 13 RCTs (4273 STEMI patients) were identified and divided into 2 subgroups: intracoronary adenosine versus control (8 RCTs) and intravenous adenosine versus control (5 RCTs). In patients administered intracoronary adenosine, the incidence of heart failure was significantly lower (risk ratio [RR] 0.44 [95% CI 0.25–0.78], P = 0.005) and the incidence of coronary no-reflow was reduced (RR for TIMI flow<3 postreperfusion 0.68 [95% CI 0.47–0.99], P = 0.04). There was no difference in heart failure incidence in the intravenous adenosine group but most RCTs in this subgroup were from the thrombolysis era. There was no difference in non-fatal MI or all-cause mortality in both subgroups. Conclusion We find evidence of improved clinical outcome in terms of less heart failure in STEMI patients administered intracoronary adenosine as an adjunct to reperfusion. This finding will need to be confirmed in a large adequately powered prospective RCT.

Automated Extracellular Volume Fraction Mapping Provides Insights Into the Pathophysiology of Left Ventricular Remodeling Post–Reperfused ST‐Elevation Myocardial Infarction

Background Whether the remote myocardium of reperfused ST‐segment elevation myocardial infarction (STEMI) patients plays a part in adverse left ventricular (LV) remodeling remains unclear. We aimed to use automated extracellular volume fraction (ECV) mapping to investigate whether changes in the ECV of the remote (ECVR emote) and infarcted myocardium (ECVI nfarct) impacted LV remodeling. Methods and Results Forty‐eight of 50 prospectively recruited reperfused STEMI patients completed a cardiovascular magnetic resonance at 4±2 days and 40 had a follow‐up scan at 5±2 months. Twenty healthy volunteers served as controls. Mean segmental values for native T1, T2, and ECV were obtained. Adverse LV remodeling was defined as ≥20% increase in LV end‐diastolic volume. ECVR emote was higher on the acute scan when compared to control (27.9±2.1% vs 26.4±2.1%; P=0.01). Eight patients developed adverse LV remodeling and had higher ECVR emote acutely (29.5±1.4% vs 27.4±2.0%; P=0.01) and remained higher at follow‐up (28.6±1.5% vs 26.6±2.1%; P=0.02) compared to those without. Patients with a higher ECVR emote and a lower myocardial salvage index (MSI) acutely were significantly associated with adverse LV remodeling, independent of T1Remote, T1Core and microvascular obstruction, whereas a higher ECVI nfarct was significantly associated with worse wall motion recovery. Conclusions ECVR emote was increased acutely in reperfused STEMI patients. Those with adverse LV remodeling had higher ECVR emote acutely, and this remained higher at follow‐up than those without adverse LV remodeling. A higher ECVR emote and a lower MSI acutely were significantly associated with adverse LV remodeling whereas segments with higher ECVI nfarct were less likely to recover wall motion.

Impact of microvascular obstruction on semiautomated techniques for quantifying acute and chronic myocardial infarction by cardiovascular magnetic resonance.

Aims The four most promising semiautomated techniques (5-SD, 6-SD, Otsu and the full width half maximum (FWHM)) were compared in paired acute and follow-up cardiovascular magnetic resonance (CMR), taking into account the impact of microvascular obstruction (MVO) and using automated extracellular volume fraction (ECV) maps for reference. Furthermore, their performances on the acute scan were compared against manual myocardial infarct (MI) size to predict adverse left ventricular (LV) remodelling (≥20% increase in end-diastolic volume). Methods 40 patients with reperfused ST segment elevation myocardial infarction (STEMI) with a paired acute (4±2 days) and follow-up CMR scan (5±2 months) were recruited prospectively. All CMR analysis was performed on CVI42. Results Using manual MI size as the reference standard, 6-SD accurately quantified acute (24.9±14.0%LV, p=0.81, no bias) and chronic MI size (17.2±9.7%LV, p=0.88, no bias). The performance of FWHM for acute MI size was affected by the acquisition sequence used. Furthermore, FWHM underestimated chronic MI size in those with previous MVO due to the significantly higher ECV in the MI core on the follow-up scans previously occupied by MVO (82 (75–88)% vs 62 (51–68)%, p<0.001). 5-SD and Otsu were precise but overestimated acute and chronic MI size. All techniques were performed with high diagnostic accuracy and equally well to predict adverse LV remodelling. Conclusions 6-SD was the most accurate for acute and chronic MI size and should be the preferred semiautomatic technique in randomised controlled trials. However, 5-SD, FWHM and Otsu could also be used when precise MI size quantification may be adequate (eg, observational studies).

Diagnostic performance of T 1 and T 2 mapping to detect intramyocardial hemorrhage in reperfused ST-segment elevation myocardial infarction (STEMI) patients: T 1 and T 2 Mapping and IMH

To investigate the performance of T1 and T2 mapping to detect intramyocardial hemorrhage (IMH) in ST‐segment elevation myocardial infarction (STEMI) patients treated by primary percutaneous coronary intervention (PPCI).

Association of different antiplatelet therapies with mortality after primary percutaneous coronary intervention

Objectives Prasugrel and ticagrelor both reduce ischaemic endpoints in high-risk acute coronary syndromes, compared with clopidogrel. However, comparative outcomes of these two newer drugs in the context of primary percutaneous coronary intervention (PCI) for ST-elevation myocardial infarction (STEMI) remains unclear. We sought to examine this question using the British Cardiovascular Interventional Society national database in patients undergoing primary PCI for STEMI. Methods Data from January 2007 to December 2014 were used to compare use of P2Y12 antiplatelet drugs in primary PCI in >89 000 patients. Statistical modelling, involving propensity matching, multivariate logistic regression (MLR) and proportional hazards modelling, was used to study the association of different antiplatelet drug use with all-cause mortality. Results In our main MLR analysis, prasugrel was associated with significantly lower mortality than clopidogrel at both 30 days (OR 0.87, 95% CI 0.78 to 0.97, P=0.014) and 1 year (OR 0.89, 95% CI 0.82 to 0.97, P=0.011) post PCI. Ticagrelor was not associated with any significant differences in mortality compared with clopidogrel at either 30 days (OR 1.07, 95% CI 0.95 to 1.21, P=0.237) or 1 year (OR 1.058, 95% CI 0.96 to 1.16, P=0.247). Finally, ticagrelor was associated with significantly higher mortality than prasugrel at both time points (30 days OR 1.22, 95% CI 1.03 to 1.44, P=0.020; 1 year OR 1.19 95% CI 1.04 to 1.35, P=0.01). Conclusions In a cohort of over 89 000 patients undergoing primary PCI for STEMI in the UK, prasugrel is associated with a lower 30-day and 1-year mortality than clopidogrel and ticagrelor. Given that an adequately powered comparative randomised trial is unlikely to be performed, these data may have implications for routine care.

Redefining viability by cardiovascular magnetic resonance in acute ST-segment elevation myocardial infarction

In chronic myocardial infarction (MI), segments with a transmural extent of infarct (TEI) of ≤50% are defined as being viable. However, in the acute phase of an ST-segment elevation myocardial infarction (STEMI), late gadolinium enhancement (LGE) has been demonstrated to overestimate MI size and TEI. We aimed to identify the optimal cut-off of TEI by cardiovascular magnetic resonance (CMR) for defining viability during the acute phase of an MI, using ≤50% TEI at follow-up as the reference standard. 40 STEMI patients reperfused by primary percutaneous coronary intervention (PPCI) underwent a CMR at 4 ± 2 days and 5 ± 2 months. The large majority of segments with 1–25%TEI and 26–50%TEI that were viable acutely were also viable at follow-up (59/59, 100% and 75/82, 96% viable respectively). 56/84(67%) segments with 51–75%TEI but only 4/63(6%) segments with 76–100%TEI were reclassified as viable at follow-up. TEI on the acute CMR scan had an area-under-the-curve of 0.87 (95% confidence interval of 0.82 to 0.91) and ≤75%TEI had a sensitivity of 98% but a specificity of 66% to predict viability at follow-up. Therefore, the optimal cut-off by CMR during the acute phase of an MI to predict viability was ≤75% TEI and this would have important implications for patients undergoing viability testing prior to revascularization during the acute phase.

The Pyramid of Danger: The Value of TEE in Detecting Risk of Aortic Perforation during TAVI

An 87-year-old man undergoing transcatheter aortic valve implantation (TAVI) for severe aortic stenosis was noted to have bulky calcification of the noncoronary aortic cusp, extending into the corresponding sinus, on transesophageal echocardiography (TEE). During balloon valvuloplasty, TEE demonstrated displacement of this calcium into the aortic wall, producing a distinctive pyramidal indentation and indicating threatened focal aortic perforation. Importantly, this hazard was not evident on corresponding x-ray cine-angiography and emphasizes the value of TEE in guiding TAVI procedures. This information allowed alteration in deployment technique for the TAVI valve and forewarned the team to increased risk of a major hazard at this stage.