Percutaneous management of coronary bifurcation lesions: current perspective.

PURPOSE OF REVIEW: Coronary artery disease affecting bifurcations poses a challenge for percutaneous intervention. Several techniques and strategies for percutaneous management of bifurcation lesions have been described in the literature with variable data available for outcomes. In this review, we provide an overview of the strategies and techniques used for percutaneous intervention of bifurcation lesions with an update of recent technical developments and clinical evidence. RECENT FINDINGS: The coronary bifurcation lesions of both left main and other coronary segments are best treated with a provisional stenting strategy where main branch is treated with a stent placement and side branch intervention reserved for angiographically or physiologically determined hemodynamically significant residual stenosis despite application of a proximal stent optimization technique. When a provisional stent strategy is not likely to be successful due to anatomic or morphologic lesion characteristics and a large side branch or distal left main bifurcation is involved, an upfront bifurcation stenting strategy with double kissing crush technique may provide the optimum results. Coronary imaging and fractional flow determination may guide lesion specific management, facilitate device selection and improve clinical outcomes for percutaneous therapy for bifurcation lesions. SUMMARY: Despite advances in technology and procedural techniques, percutaneous intervention of coronary bifurcation lesions remains challenging and associated with higher adverse outcomes compared to non bifurcation lesions. Among the several bifurcation strategies, a provisional stenting approach is preferred for technical simplicity and better long term outcomes. Double kissing crush technique provides superior clinical results and should be preferred when a two stent strategy is indicated. Use of coronary imaging and physiology assessment should be incorporated in the algorithm of bifurcation interventions for greater technical and clinical success.

The Utility of Systolic and Diastolic Echocardiographic Parameters for Predicting Coronary Artery Disease Burden as Defined by the SYNTAX Score.

BACKGROUND: Early identification of high-grade ischemia based on echocardiographic diastolic abnormalities may be clinically useful in the acute coronary syndrome (ACS) setting. This could provide the clinician with an awareness of the burden of coronary artery disease (CAD) before angiography is performed to allow for early intervention of suspected ischemic lesions. The objective of the study was to assess whether 2D transthoracic echocardiography (TTE)-derived tissue Doppler imaging parameters can predict the severity of CAD in comparison with the cardiac catheterization-derived SYNTAX score. METHODS: A retrospective study of 74 stable angina or patients with ACS was performed in 2012 at a single tertiary care center. In all study subjects, TTE and angiography were performed within 6 months of each other without revascularization in the interim. RESULTS: The study population included a total of 74 patients (mean age 67 ± 12 years) with 77% presenting with an ACS. The median SYNTAX score was 24.0 (6.0-35.0). The E-wave velocity was higher, and deceleration time (DT) was lower in the high SYNTAX group in comparison with the low/intermediate SYNTAX group (P = 0.045 and P = 0.001, respectively). Septal mitral annular S' was lower in the high SYNTAX group (P = 0.02). After multivariate analysis, E/A ratio (OR 0.03, 95% 0.00-0.36, P = 0.0067), DT (OR 0.93, 95% CI 0.89-0.97, P = 0.0001) and septal annular S'-wave velocity (OR 0.34, 95% CI 0.16-0.71, P = 0.0038) remained strong predictors of a high SYNTAX score. CONCLUSION: Early identification of systolic and diastolic dysfunction based on echocardiographic parameters may be of important clinical significance for predicting CAD burden prior to invasive angiography.

The Learning Curve and Annual Procedure Volume Standards for Optimum Outcomes of Transcatheter Aortic Valve Replacement: Findings From an International Registry.

OBJECTIVES: The authors aimed to determine the procedural learning curve and minimum annual institutional volumes associated with optimum clinical outcomes for transcatheter aortic valve replacement (TAVR). BACKGROUND: Transcatheter aortic valve replacement (TAVR) is a complex procedure requiring significant training and experience for successful outcome. Despite increasing use of TAVR across institutions, limited information is available for its learning curve characteristics and minimum annual volumes required to optimize clinical outcomes. METHODS: The study collected data for patients at 16 centers participating in the international TAVR registry since initiation of the respective TAVR program. All cases were chronologically ordered into initial (1 to 75), early (76 to 150), intermediate (151 to 225), high (226 to 300), and very high (>300) experience operators for TAVR learning curve characterization. In addition, participating institutions were stratified by annual TAVR case volume into low-volume (<50), moderate-volume (50 to 100), and high-volume (>100) groups for comparative analysis. Procedural and 30-day clinical outcomes were collected and multivariate regression analysis performed for 30-day mortality and the early safety endpoint. RESULTS: A total of 3,403 patients comprised the study population. On multivariate analysis, all-cause mortality was significantly higher for initial (odds ratio [OR]: 3.83; 95% confidence interval [CI]: 1.93 to 7.60), early (OR: 2.41; 95% CI: 1.51 to 5.03), and intermediate (OR: 2.53; 95% CI: 1.19 to 5.40) experience groups compared with the very high experience operators. In addition, the early safety endpoint was significantly worse for all experience groups compared with the very high experience operators. Low annual volume (<50) TAVR institutions had significantly higher all-cause 30-day mortality (OR: 2.70; 95% CI: 1.44 to 5.07) and worse early safety endpoint (OR: 1.60; 95% CI: 1.17 to 2.17) compared with the moderate- and high-volume groups. There was no difference in patient outcomes between intermediate and high annual volume groups. CONCLUSIONS: TAVR procedures display important learning curve characteristics with both greater procedural safety and a lower mortality when performed by experienced operators. In addition, TAVR performed at low annual volume (<50 procedures) institutions is associated with decreased procedural safety and higher patient mortality. These findings have important implications for operator training and patient care at centers performing TAVR.

Institutional experience and outcomes of transcatheter aortic valve replacement: Results from an international multicentre registry.

BACKGROUND: Despite rapidly increasing use of TAVR across institutions, limited data is available for the effect of procedural experience on TAVR outcomes. We investigate the relationship between institutional experience and TAVR outcomes. METHODS: 1953 patients undergoing TAVR at 8 international sites were grouped into chronological quantiles (Q) to assess temporal changes on procedural and clinical outcomes and multivariate logistic regression performed to determine predictors of device success, early safety and all-cause mortality. RESULTS: The mean age of patients was 81±7years and 991 (51%) were female. The quantiles comprised of first 62 cases for Q1, 63-133 for Q2, 134 to 242 for Q3 and 243 to 476 for Q4. Device success increased from Q1 to Q4 (78% vs 89%, p<0.001) with significant improvement in the early safety endpoint (19% vs 10%, p<0.001). All cause mortality reduced by half in Q4 compared to Q1 (8% vs 4%, p=0.01) and rates of major vascular complications, major bleeding and valve embolization decreased with increasing experience. The multivariate analysis identified TAVR in Q3 and Q4 to be independently associated with higher device success and lower risk of complications. TAVR in Q4 was independently associated with lower mortality (OR 0.36 95% CI 0.19-0.70, p=0.002). CONCLUSIONS: Greater institutional experience with TAVR procedures improves device success and clinical outcomes. An experience of >242 cases is independently associated with lower mortality. These findings have important implications for defining minimum volume criteria for institutions and training standards for TAVR procedure.

Short Duration vs Standard Duration of Dual-Antiplatelet Therapy After Percutaneous Coronary Intervention With Second-Generation Drug-Eluting Stents - A Systematic Review, Meta-Analysis, and Meta-Regression Analysis of Randomized Controlled Trials.

BACKGROUND: Current guidelines recommend 12 months of dual-antiplatelet therapy (DAPT) after percutaneous coronary intervention (PCI) with drug-eluting stent (DES) implantation. Whether the duration of DAPT can be safely shortened with use of second-generation DESs is unclear. METHODS: We conducted a meta-analysis of randomized controlled trials comparing short duration (SD) (3-6 months) with standard longer duration (LD) (≥12 months) DAPT in patients treated with primarily second-generation DES implantation. Meta-regression was performed to explore the relationship between acute coronary syndrome (ACS) and the effect of DAPT duration. RESULTS: Six studies were included, with 12,752/13,928 (91.5%) patients receiving second-generation DESs. A total of 5367 patients (39%) had PCI in the setting of ACS. There was no difference in all-cause mortality (1.1% vs 1.2%; odds ratio [OR], 0.86; 95% confidence interval [CI], 0.63-1.18; P=.36) or cardiac mortality (0.9% vs 1.0%; OR, 0.92; 95% CI, 0.61-1.39; P=.69) with SD-DAPT vs LD-DAPT, respectively. Definite/probable stent thrombosis (0.5% vs 0.3%; OR, 1.33; 95% CI, 0.75-2.34; P=.51), myocardial infarction (1.5% vs 1.3%; OR, 1.17; 95% CI, 0.88-1.56; P=.29), and stroke (0.4% vs 0.4%; OR, 1.04; 95% CI, 0.60-1.81; P=.88) were similar between the groups. Compared with LD-DAPT, SD-DAPT was associated with lower clinically significant bleeding (0.9% vs 1.4%; OR, 0.64; 95% CI, 0.46-0.89; P=.01). Meta-regression analysis showed no significant association between the proportion of ACS patients in trials and duration of DAPT for the outcomes of mortality (P=.95), myocardial infarction (P=.98), or stent thrombosis (P=.89). CONCLUSION: In low-risk patients treated with contemporary second-generation DES implantation, SD-DAPT has similar rates of mortality, myocardial infarction, and stent thrombosis, with lower rates of bleeding compared with LD-DAPT.

Transcatheter Tricuspid Repair With MitraClip for Severe Primary Tricuspid Regurgitation.

Severe tricuspid regurgitation is an independent predictor of adverse outcomes, yet few patients undergo surgery and treatment with medical therapy is often inadequate. Recent studies have reported the use of the MitraClip system (Abbott Vascular) to treat secondary tricuspid regurgitation. We describe the first use of MitraClip to treat severe primary tricuspid regurgitation and right heart failure in a patient with previous cardiac transplantation and high surgical risk.

An unusual cause of ventricular tachycardia: Port-A-Cath fracture and embolization into the pulmonary artery.

We describe the case of a patient with a previously placed Port-A-Cath who was admitted to hospital for new onset of non-flushing catheter and palpitations with ventricular tachycardia. A chest X-ray and a linogram showed a Port-A-Cath fracture and distal embolization into the right ventricle resulting in ventricular tachycardia. The catheter was removed percutaneously using a Goose Neck snare with no complications and resolution of the ventricular tachycardia. The removed segment demonstrated thrombus. Prompt removal of the embolized catheter fragments should be undertaken given the subtle nature of the embolization and the potential complications.

The double helix angiography of right coronary arteries: false lumen stenting of a type F right coronary artery spiral dissection with late recanalization of the true lumen and occlusion of the stented false lumen.

Guide catheter induced dissection of coronary arteries is an uncommon, but serious complication of coronary angioplasty. Treatment can include emergent coronary artery bypass grafting to the affected vessel or percutaneous intervention including wiring the true lumen and exclusion stenting of the dissection flap to prevent further propagation. Detailed descriptions have been published of techniques of intentional passage of guide wires into the false lumen and reentry into the true lumen with chronic total occlusions. We present an unusual case of what appeared to be successful intentional false lumen stenting with reentry into the true lumen of an iatrogenic dissection of the right coronary artery with restoration of TIMI III coronary flow which, one year later, was complicated by recanalization of the true lumen and occlusion of the stented false lumen causing symptomatic angina.

Radiation dose reduction in the cardiac catheterization laboratory utilizing a novel protocol.

OBJECTIVES: This study reports the results a novel radiation reduction protocol (RRP) system for coronary angiography and interventional procedures and the determinants of radiation dose. BACKGROUND: The cardiac catheterization laboratory is an important source of radiation and should be kept in good working order with dose-reduction and monitoring capabilities. METHODS: All diagnostic coronary angiograms and percutaneous coronary interventions from a single catheterization laboratory were analyzed 2 months before and after RRP implementation. The primary outcome was the relative dose reduction at the interventional reference point. Separate analyses were done for conventional 15 frames/s (FPS) and at reduced 7.5 FPS post-RRP groups. RESULTS: A total of 605 patients underwent coronary angiography (309 before RRP and 296 after RRP), with 129 (42%) and 122 (41%) undergoing percutaneous coronary interventions before and after RRP, respectively. With RRP, a 48% dose reduction (1.07 ± 0.05 Gy vs. 0.56 ± 0.03 Gy, p < 0.0001) was obtained, 35% with 15 FPS RRP (0.70 ± 0.05 Gy, p < 0.0001) and 62% with 7.5 FPS RRP (0.41 ± 0.03 Gy, p < 0.001). Similar dose reductions for diagnostic angiograms and percutaneous coronary interventions were noted. There was no change in the number of stents placed or vessels intervened on. Increased dose was associated with male sex, radial approach, increasing body mass index, cine runs, and frame rates. Using a multivariable model, a 48% relative risk with RRP (p < 0.001), 44% with 15 FPS RRP and 68% with 7.5 FPS RRP was obtained. CONCLUSIONS: We demonstrate a highly significant 48.5% adjusted radiation dose reduction using a novel algorithm, which needs strong consideration among interventional cardiology practice.

Functional mitral regurgitation: current understanding and approach to management.

Functional mitral regurgitation (FMR) is a challenging clinical entity that frequently complicates ischemic and nonischemic cardiomyopathy. The underlying pathophysiology of FMR is caused primarily by ventricular and subvalvular apparatus dysfunction which causes failure of proper leaflet coaptation. Echocardiography is the primary modality used in diagnosis and characterization of FMR. Echocardiography allows for assessment of valvular and ventricular structures and their interaction. FMR portends a poor prognosis, because it is frequently associated with increased morbidity and mortality. The optimal management of FMR involves an individualized approach that incorporates medical therapy and consideration of surgical, percutaneous, and resynchronization therapies according to the severity of regurgitation, presence of symptoms, option for revascularization, and the degree of ventricular remodelling.

The Learning Curve and Annual Procedure Volume Standards for Optimum Outcomes of Transcatheter Aortic Valve Replacement: Findings From an International Registry

OBJECTIVES: The authors aimed to determine the procedural learning curve and minimum annual institutional volumes associated with optimum clinical outcomes for transcatheter aortic valve replacement (TAVR).BACKGROUND: Transcatheter aortic valve replacement (TAVR) is a complex procedure requiring significant training and experience for successful outcome. Despite increasing use of TAVR across institutions, limited information is available for its learning curve characteristics and minimum annual volumes required to optimize clinical outcomes. METHODS: The study collected data for patients at 16 centers participating in the international TAVR registry since initiation of the respective TAVR program. All cases were chronologically ordered into initial (1 to 75), early (76 to 150), intermediate (151 to 225), high (226 to 300), and very high (>300) experience operators for TAVR learning curve characterization. In addition, participating institutions were stratified by annual TAVR case volume into low-volume (<50), moderate-volume (50 to 100), and high-volume (>100) groups for comparative analysis. Procedural and 30-day clinical outcomes were collected and multivariate regression analysis performed for 30-day mortality and the early safety endpoint. RESULTS: A total of 3,403 patients comprised the study population. On multivariate analysis, all-cause mortality was significantly higher for initial (odds ratio [OR]: 3.83; 95% confidence interval [CI]: 1.93 to 7.60), early (OR: 2.41; 95%CI: 1.51 to 5.03), and intermediate (OR: 2.53; 95% CI: 1.19 to 5.40) experience groups compared with the very high experience operators. In addition, the early safety endpoint was significantly worse for all experience groups compared with the very high experience operators. Low annual volume (<50) TAVR institutions had significantly higher all-cause30-day mortality (OR: 2.70; 95% CI: 1.44 to 5.07) and worse early safety endpoint (OR: 1.60; 95% CI: 1.17 to 2.17) compared with the moderate- and high-volume groups. There was no difference in patient outcomes between intermediate and high annual volume groups. CONCLUSIONS: TAVR procedures display important learning curve characteristics with both greater procedural safety and a lower mortality when performed by experienced operators. In addition, TAVR performed at low annual volume (<50 procedures) institutions is associated with decreased procedural safety and higher patient mortality. These findings have important implications for operator training and patient care at centers performing TAVR.

To transmit or not to transmit: how good are emergency medical personnel in detecting STEMI in patients with chest pain?

BACKGROUND: There is growing use of prehospital electrocardiograms (ECGs) in establishing early diagnosis of ST segment myocardial infarction (STEMI) to facilitate early reperfusion. This study aimed to determine the predictive value of prehospital ECGs interpreted by nonphysician emergency medical services (EMS) in chest pain presentations. METHODS: In our city of 658,700 people, EMS/paramedics received 21 hours of instruction on STEMI management, ECG acquisition, and interpretation. Suspected STEMI ECGs were wirelessly transmitted to and discussed with a physician for possible therapy. ECGs deemed negative for STEMI by EMS were not transmitted; patients were transported to the closest hospital without prehospital physician involvement. RESULTS: From July 21, 2008 to July 21, 2010, there were 5426 chest pain calls to EMS, 380 were suspected STEMI cases. The remaining ECGs were deemed negative for STEMI by EMS. To audit the nontransmitted ECGs we analyzed 323 consecutive patients over 2 selected months (January and June 2010) for comparison. Of nontransmitted cases there was 1 missed and 2 STEMIs that developed subsequently. Based on 380 transmitted and 323 nontransmitted cases, the sensitivity and specificity of EMS detecting STEMI were 99.6% and 67.6%, respectively. The positive and negative predictive values for STEMI were 59.5% and 99.7%, respectively. CONCLUSIONS: Our findings demonstrate nonphysician EMS interpretation of STEMI on prehospital ECG has excellent sensitivity and high negative predictive value. This finding supports the use of prehospital ECGs interpreted by EMS to help identify and facilitate treatment of STEMI. These results may have broad implications on staffing models for first responder/EMS units.

Cardiac Outcomes Through Digital Evaluation (CODE) STEMI project: prehospital digitally-assisted reperfusion strategies.

BACKGROUND: Guidelines for reperfusion in ST-elevation myocardial infarction (STEMI) were recently adopted by the Canadian Cardiovascular Society. We have developed a blended model of prehospital thrombolytic (PHL) therapy or primary percutaneous coronary intervention (PPCI) activation, in order to achieve guideline times. METHODS: In our urban centre of 658,700 people, emergency medical services (EMS) were trained to perform and screen electrocardiograms (ECGs) for suspected STEMI. Suspected ECGs were transmitted to a physician's hand-held device. If the physician confirmed the diagnosis they coordinated initiation of either PHL or PPCI. In cases where physicians found the prehospital ECG negative for STEMI (PHENST), patients were transported to the closest emergency room. RESULTS: From July 21, 2008 to July 21, 2010, the Cardiac Outcomes Through Digital Evaluation (CODE) STEMI project received 380 transmitted calls. There were 226 confirmed STEMI by the on-call physician, 158 (70%) received PPCI, 48 (21%) received PHL, and 20 (9%) had angiography but no revascularization. The PPCI, median time from first medical contact to reperfusion was 76 minutes (interquartile range [IQR], 64-93). For PHL, median time from first medical contact to needle was 32 minutes (IQR, 29-39). The overall mortality rate for the STEMI patients was 8% (PHL = 4 [8.3%], PPCI = 8 [5%], medical therapy = 7 [35%]). There were 154 PHENST patients, 44% later diagnosed with acute coronary syndrome. The mortality rate for PHENST was 14%. CONCLUSIONS: Through a model of EMS prehospital ECG interpretation, digital transmission, direct communication with a physician, and rapid coordinated service, we demonstrate that benchmark reperfusion times in STEMI can be achieved.