Neil Fam

Characterization of Operator Learning Curve for Transradial Coronary Interventions

Background—Transradial percutaneous coronary intervention (TR-PCI) improves clinical outcomes compared to the transfemoral (TF) approach. However, inadequate training and experience has limited widespread adoption by interventional cardiologists. Methods and Results—Clinical and procedural characteristics for TR-PCI were prospectively collected from 1999 to 2008. To identify minimum case volume for optimum clinical benefit, single-vessel TR-PCI cases were chronologically ranked and stratified into 1 to 50, 51 to 100, 101 to 150 and 151 to 300 case volume groups for operators starting the TR approach at the study institution. Cases by operators with a >300 TR-PCI case volume comprised the control group. TR-PCI failure rates, contrast use, guide usage, and fluoroscopy time were compared among groups. A total of 1672 patients underwent TR-PCI by 28 operators. TR-PCI failure occurred in 4% and was higher in the 1 to 50 case volume group compared to the 51 to 100 (P=0.007) and control (P=0.01) groups. Contrast use was greater in the 1 to 50 group (180±79 mL) compared to the 151 to 300 (157±75 mL, P=0.02) and control (168±79 mL, P=0.05) groups. Fluoroscopy time was higher in the 1 to 50 group (15±10 minutes) compared to the 101 to 150 (13±10 minutes, P=0.04) and control (12±9 minutes, P=0.02) groups. Reasons for TR-PCI failure included spasm (38%), subclavian tortuousity (16%), poor guide support (16%), failed access (10%), and radial loop (7%). Case volume was significantly correlated with TR-PCI failure (&bgr;=−0.0076, P=0.0028), and odds of failure was reduced by 32% for each 50 increments in case volume. Conclusions—TR-PCI success depends on operator experience, and a case volume of ≥50 cases is required to achieve outcomes comparable to experienced operators. These findings have implications both for PCI operators looking to expand their skills and for defining standards for training.

Mechanism and Predictors of Failed Transradial Approach for Percutaneous Coronary Interventions

OBJECTIVES The study aimed to determine the mechanism and predictors of procedural failure in patients undergoing percutaneous coronary intervention (PCI) from the transradial approach (TR). BACKGROUND Transradial approach PCI reduces vascular complications compared with a transfemoral approach (TF). However, the mechanism and predictors of TR-PCI failure have not been well-characterized. METHODS The study population consisted of patients undergoing TR-PCI by low-to-intermediate volume operators with traditional TF guide catheters. Baseline characteristics, procedure details, and clinical outcomes were prospectively collected. Univariate and multivariate analyses were performed to determine independent predictors of TR-PCI failure. RESULTS A total of 2,100 patients underwent TR-PCI and represented 38% of PCI volume. Mean age was 64 +/- 12 years, and 17% were female. Vascular complications occurred in 22 (1%), and TR-PCI failure was observed in 98 (4.7%) patients. The mechanism of TR-PCI failure included inability to advance guide catheter to ascending aorta in 50 (51%), inadequate guide catheter support in 35 (36%), and unsuccessful radial artery puncture in 13 (13%) patients. The PCI was successful in 94 (96%) patients with TR-PCI failure by switching to TF. On multivariate analysis, age >75 years (odds ratio [OR]: 3.86; 95% confidence interval [CI]: 2.33 to 6.40, p = 0.0006), prior coronary artery bypass graft surgery (OR: 7.47; 95% CI: 3.45 to 16.19, p = 0.0002), and height (OR: 0.97; 95% CI: 0.95 to 0.99, p = 0.02) were independent predictors of TR-PCI failure. CONCLUSIONS Transradial approach PCI can be performed by low-to-intermediate volume operators with standard equipment with a low failure rate. Age >75 years, prior coronary artery bypass graft surgery, and short stature are independent predictors of TR-PCI failure. Appropriate patient selection and careful risk assessment are needed to maximize benefits offered by TR-PCI.

Transcatheter Treatment of Severe Tricuspid Regurgitation with the Edge-to-Edge: MitraClip Technique.

Background: Current surgical and medical treatment options for severe tricuspid regurgitation (TR) are limited, and additional interventional approaches are required. In the present observational study, the safety and feasibility of transcatheter repair of chronic severe TR with the MitraClip system were evaluated. In addition, the effects on clinical symptoms were assessed. Methods: Patients with heart failure symptoms and severe TR on optimal medical treatment were treated with the MitraClip system. Safety, defined as periprocedural adverse events such as death, myocardial infarction, stroke, or cardiac tamponade, and feasibility, defined as successful implantation of 1 or more MitraClip devices and reduction of TR by at least 1 grade, were evaluated before discharge and after 30 days. In addition, functional outcome, defined as changes in New York Heart Assocation class and 6-minute walking distance, were assessed. Results: We included 64 consecutive patients (mean age 76.6±10 years) deemed unsuitable for surgery who underwent MitraClip treatment for chronic, severe TR for compassionate use. Functional TR was present in 88%; in addition, 22 patients were also treated with the MitraClip system for mitral regurgitation as a combined procedure. The degree of TR was severe or massive in 88% of patients before the procedure. The MitraClip device was successfully implanted in the tricuspid valve in 97% of the cases. After the procedure, TR was reduced by at least 1 grade in 91% of the patients, thereof 4% that were reduced from massive to severe. In 13% of patients, TR remained severe after the procedure. Significant reductions in effective regurgitant orifice area (0.9±0.3cm2 versus 0.4±0.2cm2; P<0.001), vena contracta width (1.1±0.5 cm versus 0.6±0.3 cm; P=0.001), and regurgitant volume (57.2±12.8 mL/beat versus 30.8±6.9 mL/beat; P<0.001) were observed. No intraprocedural deaths, cardiac tamponade, emergency surgery, stroke, myocardial infarction, or major vascular complications occurred. Three (5%) in-hospital deaths occurred. New York Heart Association class was significantly improved (P<0.001), and 6-minute walking distance increased significantly (165.9±102.5 m versus 193.5±115.9 m; P=0.007). Conclusions: Transcatheter treatment of TR with the MitraClip system seems to be safe and feasible in this cohort of preselected patients. Initial efficacy analysis showed encouraging reduction of TR, which may potentially result in improved clinical outcomes.

Transcatheter mitral valve implantation (TMVI) using the Edwards FORTIS device.

Transcatheter aortic valve implantation (TAVI) has demonstrated the feasibility of treating valvular heart disease with transcatheter therapy. On the back of this success, various transcatheter concepts are being evaluated to treat other valvular disease, especially mitral regurgitation (MR). The concepts currently approved to treat MR replicate surgical mitral valve repair. However, most of them cannot eliminate MR completely. Similar to TAVI, a transcatheter mitral valve implantation may provide a valuable alternative. The FORTIS transcatheter mitral valve (Edwards Lifesciences, Irvine, CA, USA) is a self-expanding device implanted via a transapical approach. We describe our experience and early results in the first five patients treated on compassionate grounds. We also describe the details of the device, selection criteria and technical details of implantation.

Characterization of clopidogrel hypersensitivity reactions and management with oral steroids without clopidogrel discontinuation.

OBJECTIVES The purpose of this study was to characterize clopidogrel hypersensitivity and describe its successful management with oral steroids without clopidogrel discontinuation. BACKGROUND Hypersensitivity reactions to clopidogrel are poorly understood and present difficulty in management. METHODS Patients diagnosed with clopidogrel hypersensitivity after percutaneous coronary intervention underwent evaluation and received oral prednisone without clopidogrel discontinuation. Cutaneous testing was performed after completion of clopidogrel therapy for diagnosis and assessment of cross-reactivity. RESULTS Sixty-two patients representing 1.6% of the percutaneous coronary intervention population developed clopidogrel hypersensitivity during the study period. The mean age was 62 ± 11 years, 71% of patients were male, and 35% reported prior adverse drug reaction. Clopidogrel hypersensitivity manifested as generalized exanthema in 79%, localized skin reaction in 16%, and angioedema or urticaria in 5% of patients. Biopsy of affected areas demonstrated a lymphocyte-mediated delayed hypersensitivity reaction. Complete resolution of hypersensitivity reaction was observed in 61 patients (98%) with a short course of oral prednisone. Cutaneous testing confirmed delayed hypersensitivity reaction to clopidogrel in 34 (81%) and immediate hypersensitivity in 3 of 42 patients (7%) tested. Allergenic cross-reactivity was observed for ticlopidine in 10 (24%), prasugrel in 7 (17%), and both ticlopidine and prasugrel in 3 patients (7%). Histological examination showed lymphocyte-mediated hypersensitivity in abnormal patch test areas. CONCLUSIONS Clopidogrel hypersensitivity is manifested as generalized exanthema and is caused by a lymphocyte-mediated delayed hypersensitivity in most patients. This can be managed with oral steroids without clopidogrel discontinuation. Allergenic cross-reactivity with ticlopidine, prasugrel, or both is present in a significant number of patients with clopidogrel hypersensitivity.

Compassionate use of the PASCAL transcatheter mitral valve repair system for patients with severe mitral regurgitation: a multicentre, prospective, observational, first-in-man study

BACKGROUND Severe mitral regurgitation is associated with impaired prognosis if left untreated. Using the devices currently available, transcatheter mitral valve repair (TMVr) remains challenging in complex anatomical situations. We report the procedural and 30-day results of the first-in-man study of the Edwards PASCAL TMVr system. METHODS In this multicentre, prospective, observational, first-in-man study, we collected data from seven tertiary care hospitals in five countries that had a compassionate use programme in which patients underwent transcatheter mitral valve repair using the Edwards PASCAL TMVr system. Eligible patients were those with symptomatic, severe functional, degenerative, or mixed mitral regurgitation deemed at high risk or inoperable. Safety and efficacy of the procedure were prospectively assessed at device implantation, discharge, and 30 days after device implantation. The key study endpoints were technical success assessed at the end of the procedure and device success 30 days after implantation using the Mitral Valve Academic Research Consortium definitions. FINDINGS Between Sept 1, 2016, and March 31, 2017, 23 patients (median age 75 years [IQR 61-82]) had treatment for moderate-to-severe (grade 3+) or severe (grade 4+) mitral regurgitation using the Edwards PASCAL TMVr system. At baseline, the median EuroScore II score was 7·1% (IQR 3·6-12·8) and the median Society of Thoracic Surgeons predicted risk of mortality for mitral valve repair was 4·8% (2·1-9·0) and 6·8% (2·9-10·1) for mitral valve replacement. 22 (96%) of 23 patients were New York Heart Association (NYHA) class III or IV at baseline. The implantation of at least one device was successful in all patients, resulting in procedural residual mitral regurgitation of grade 2+ or less in 22 (96%) patients. Six (26%) of 23 patients had two implants. Periprocedural complications occurred in two (9%) of 23 patients (one minor bleeding event and one transient ischaemic attack). Despite the anatomical complexity of mitral regurgitation in the patients in this compassionate use cohort, technical success was achieved in 22 (96%) of 23 patients, and device success at 30 days was achieved in 18 (78%) patients. Three patients (13%) died during the 30 day follow-up. 19 (95%) of 20 patients alive 30 days after implantation were NYHA class I or II. INTERPRETATION This study establishes feasibility of the Edwards PASCAL TMVr system with a high rate of technical success and reduction of mitral regurgitation severity. Further research is needed on procedural and long-term clinical outcomes. FUNDING None.

From Coronary Care Units to Cardiac Intensive Care Units: Recommendations for Organizational, Staffing, and Educational Transformation

Medical care in Canadian cardiac units has changed considerably over the past 3 decades in response to an increasingly complex and diverse patient population admitted with acute cardiac pathology. To maintain the highest level of care for these patients, there is a pressing need to evolve traditional coronary care units into contemporary cardiac intensive care units. In this article we aim to highlight the current variations in Canadian units, develop approaches to overcome logistical and infrastructural obstacles, and propose staffing and training recommendations that would allow for the establishment of contemporary cardiac intensive care units.

Interventional Treatment of Severe Tricuspid Regurgitation: Early Clinical Experience in a Multicenter, Observational, First-in-Man Study

Background— Transcatheter caval valve implantation is under evaluation as a treatment option for inoperable patients with severe tricuspid regurgitation (TR). The procedure involves the catheter-based implantation of bioprosthetic valves in the inferior vena cava and superior vena cava to treat symptoms associated with TR. This study is the first to evaluate the feasibility, safety, and efficacy of this interventional concept. Methods and Results— Twenty-five patients (mean age, 73.9±7.6 years; women, 52.0%) with severe symptomatic TR despite optimal medical treatment deemed unsuitable for surgery were treated with caval valve implantation under a compassionate clinical use program. Technical feasibility defined as procedural success, hemodynamic effect defined as venous pressure reduction, and safety defined as periprocedural adverse events were evaluated, with clinical follow-up at discharge and up to 12 months. The functional impact was evaluated by assessment of New York Heart Association class at the time of hospital discharge. The total number of valves implanted in the caval position was 31. Patients were treated with single (inferior vena cava-only; n=19; 76.0%) or bicaval valve implantation (inferior vena cava+superior vena cava; n=6; 24.0%). Either balloon-expandable valves (Sapien XT/3: n=18; 72.0%) or self-expandable valves (TricValve: n=6; 24.0%; Directflow: n=1; 4.0%) were used. Procedural success was achieved in 96% (n=24). Early and late valve migration requiring surgical intervention occurred in 1 patient each. Thirty-day and in-hospital mortality were 8% (2 of 25) and 16% (4 of 25). Causes of in-hospital mortality included respiratory (n=1) or multiple organ failure (n=3) and were not linked to the procedure. Mean overall survival in the study cohort was 316±453 days (14–1540 days). Conclusions— Caval valve implantation for the treatment of severe TR and advanced right ventricular failure is associated with a high procedural success rate and seems safe and feasible in an excessive-risk cohort. The study demonstrates hemodynamic efficacy with consistent elimination of TR-associated venous backflow and initial clinical improvement. These results encourage further trials to determine which patients benefit most from this interventional approach.

Increased myocardial expression of angiopoietin-2 in patients undergoing urgent surgical revascularization for acute coronary syndromes

BACKGROUND Myocardial ischemia triggers the expression of multiple angiogenic factors including vascular endothelial growth factor and its receptors. However, vascular endothelial growth factor does not act in isolation. OBJECTIVE To identify other genes important in the angiogenic response to clinically relevant myocardial ischemia. METHODS AND RESULTS Paired intraoperative biopsies of ischemic and nonischemic myocardium were obtained from 12 patients with acute coronary syndromes (ACS) undergoing urgent coronary artery bypass graft surgery. Real-time polymerase chain reaction demonstrated significant upregulation of angiopoietin-2 (Ang-2) in ischemic myocardium, to a greater extent than other classical angiogenic factors. Microarray gene profiling identified Ang-2 to be among the top 10 differentially upregulated genes, in addition to genes involved in inflammation, cell signalling, remodelling and apoptosis. CONCLUSIONS The present document is the first report of microarray analysis of patients with ACS, and supports an important role for Ang-2 in the angiogenic response to severe ischemia in the human heart. Common gene expression patterns in ACS may provide opportunities for targeted pharmacological and cellular intervention.

Incidence and characteristics of inappropriate and false-positive cardiac catheterization laboratory activations in a regional primary percutaneous coronary intervention program.

BACKGROUND The implementation of regional primary percutaneous coronary intervention (PCI) programs has been critical in achieving timely intervention in patients with ST-segment elevation myocardial infarction (STEMI). However, 1 consequence has been inappropriate and false-positive cardiac catheterization laboratory (CCL) activations where either angiography is cancelled or no culprit lesion is found, respectively. METHODS We performed a retrospective cohort study of 1,391 patients referred for primary PCI to a single academic center from November 2007 to August 2013. Our purpose was to determine the incidence and characteristics of inappropriate and false-positive CCL activations by emergency departments (EDs) or emergency medical services (EMS), and the effect of a quality improvement (QI) initiative to reduce such events implemented during this period. RESULTS During the study period, there were 37 (2.7%) inappropriate and 206 (14.8%) false-positive CCL activations. There was no difference between the ED and EMS rates of inappropriate activation (2.1% vs 3.8%, P = .06). Among patients who proceeded to angiography, the false-positive rate for ED CCL activation was 16.9% compared to 11.5% for EMS (P = .01). Although there was no difference comparing inappropriate activation or false-positive rates before and after the QI initiative (P = .22), we observed an encouraging year-to-year trend. CONCLUSIONS Emergency department activation of the CCL is associated with a higher false-positive rate than activation by EMS. Further QI efforts are required to improve communication between interventional cardiologists, emergency physicians, and paramedics to improve the specificity of CCL activation while taking care not to sacrifice sensitivity and rapidity of diagnosis.