Brad Munt

Percutaneous Transarterial Aortic Valve Replacement in Selected High-Risk Patients With Aortic Stenosis

Background— Percutaneous aortic valve replacement represents an endovascular alternative to conventional open heart surgery without the need for sternotomy, aortotomy, or cardiopulmonary bypass. Methods and Results— Transcatheter implantation of a balloon-expandable stent valve using a femoral arterial approach was attempted in 50 symptomatic patients with severe aortic stenosis in whom there was a consensus that the risks of conventional open heart surgery were very high. Valve implantation was successful in 86% of patients. Intraprocedural mortality was 2%. Discharge home occurred at a median of 5 days (interquartile range, 4 to 13). Mortality at 30 days was 12% in patients in whom the logistic European System for Cardiac Operative Risk Evaluation risk score was 28%. With experience, procedural success increased from 76% in the first 25 patients to 96% in the second 25 (P=0.10), and 30-day mortality fell from 16% to 8% (P=0.67). Successful valve replacement was associated with an increase in echocardiographic valve area from 0.6±0.2 to 1.7±0.4 cm2. Mild paravalvular regurgitation was common but was well tolerated. After valve insertion, there was a significant improvement in left ventricular ejection fraction (P<0.0001), mitral regurgitation (P=0.01), and functional class (P<0.0001). Improvement was maintained at 1 year. Structural valve deterioration was not observed with a median follow-up of 359 days. Conclusion— Percutaneous valve replacement may be an alternative to conventional open heart surgery in selected high-risk patients with severe symptomatic aortic stenosis.

Percutaneous Aortic Valve Implantation Retrograde From the Femoral Artery

Background— Percutaneous aortic valve implantation by an antegrade transvenous approach has been described but is problematic. Retrograde prosthetic aortic valve implantation via the femoral artery has potential advantages. Percutaneous prosthetic aortic valve implantation via the femoral arterial approach is described and the initial experience reported. Methods and Results— The valve prosthesis is constructed from a stainless steel stent with an attached trileaflet equine pericardial valve and a fabric cuff. After routine aortic balloon valvuloplasty, a 22F or 24F sheath is advanced from the femoral artery to the aorta. A steerable, deflectable catheter facilitates manipulation of the prosthesis around the aortic arch and through the stenotic valve. Rapid ventricular pacing is used to reduce cardiac output while the delivery balloon is inflated to deploy the prosthesis within the annulus. Percutaneous aortic prosthetic valve implantation was attempted in 18 patients (aged 81±6 years) in whom surgical risk was deemed excessive because of comorbidities. Iliac arterial injury, seen in the first 2 patients, did not recur after improvement in screening and access site management. Implantation was successful in 14 patients. After successful implantation, the aortic valve area increased from 0.6±0.2 to 1.6±0.4 cm2. There were no intraprocedural deaths. At follow-up of 75±55 days, 16 patients (89%) remained alive. Conclusions— This initial experience suggests that percutaneous transarterial aortic valve implantation is feasible in selected high-risk patients with satisfactory short-term outcomes.

Transcatheter Aortic Valve Implantation Impact on Clinical and Valve-Related Outcomes

Background— Transcatheter aortic valve implantation is an alternative to open heart surgery in patients with aortic stenosis. However, long-term data on a programmatic approach to aortic valve implantation remain sparse. Methods and Results— Transcatheter aortic valve implantation was performed in 168 patients (median age, 84 years) in the setting of severe aortic stenosis and high surgical risk. Access was transarterial (n=113) or, in the presence of small iliofemoral artery diameter, transapical (n=55). The overall success rate was 94.1% in this early experience. Intraprocedural mortality was 1.2%. Operative (30-day) mortality was 11.3%, lower in the transarterial group than the transapical group (8.0% versus 18.2%; P=0.07). Overall mortality fell from 14.3% in the initial half to 8.3% in the second half of the experience, from 12.3% to 3.6% (P=0.16) in transarterial patients and from 25% to 11.1% (P=0.30) in transapical patients. Functional class improved over the 1-year postprocedure period (P<0.001). Survival at 1 year was 74%. The bulk of late readmission and mortality was not procedure or valve related but rather was due to comorbidities. Paravalvular regurgitation was common but generally mild and remained stable at late follow-up. At a maximum of >3 years and a median of 221 days, structural valve failure was not observed. Conclusions— Transcatheter aortic valve implantation can result in early and sustained functional improvement in high-risk aortic stenosis patients. Late outcome is determined primarily by comorbidities unrelated to aortic valve disease.

Percutaneous Transvenous Mitral Annuloplasty Initial Human Experience With Device Implantation in the Coronary Sinus

Background— Mitral annuloplasty is the most common surgical procedure performed for ischemic mitral regurgitation (MR). Surgical mitral annuloplasty is limited by morbidity, mortality, and MR recurrence. We evaluated the safety and feasibility of a transvenous catheter-delivered implantable device to provide a percutaneous alternative to surgical mitral annuloplasty. Methods and Results— Five patients with chronic ischemic MR underwent percutaneous transvenous implantation of an annuloplasty device in the coronary sinus. Implantation was successful in 4 patients. Baseline MR in the entire group was grade 3.0±0.7 and was reduced to grade 1.6±1.1 at the last postimplantation visit when the device was intact or the last postprocedural visit in the patient in whom the device was not successfully implanted. Separation of the bridge section of the device occurred in 3 of 4 implanted devices and was detected at 28 to 81 days after implantation. There were no postprocedural device-related complications. Conclusions— Percutaneous implantation of a device intended to remodel the mitral annulus is feasible. Initial experience suggests a possible favorable effect on MR. Percutaneous transvenous mitral annuloplasty warrants further evaluation as a less invasive alternative to surgical annuloplasty.

Role of multislice computed tomography in transcatheter aortic valve replacement.

Transcatheter aortic valve replacement (TAVR) required precise knowledge of the anatomic dimensions and physical characteristics of the aortic valve, annulus, and aortic root. Most groups currently use angiography, transthoracic echocardiography (TTE), or transesophageal echocardiography (TEE) to assess aortic annulus dimensions and anatomy. However, multislice computed tomography (MSCT) may allow more detailed 3-dimensional assessment of the aortic root. Twenty-six patients referred for TAVR underwent MSCT. Scans were also obtained for 18 patients after TAVR. All patients underwent pre- and postprocedural aortic root angiography, TTE, and TEE. Mean differences in measured aortic annular diameters were 1.1 mm (95% confidence interval 0.5, 1.8) for calibrated angiography and TTE, -0.9 mm (95% confidence interval -1.7, -0.1 mm) for TTE and TEE, -0.3 mm (95% confidence interval -1.1, 0.6 mm) for MSCT (sagittal) and TTE, and -1.2 mm (95% confidence interval -2.2, -0.2 mm) for MSCT (sagittal) and TEE. Coronal systolic measurements using MSCT, which corresponded to angiographic orientation, were 3.2 mm (1st and 3rd quartiles 2.6, 3.9) larger than sagittal systolic measurements, which were in the same anatomic plane as standard TTE and TEE views. There was no significant association between either shape of the aortic annulus or amount of aortic valve calcium and development of perivalvular aortic regurgitation. After TAVR, the prosthesis extended to or beyond the inferior border of the left main ostium in 9 of 18 patients (50%), and in 11 patients (61%), valvular calcium was <5 mm from the left main ostium. In conclusion, MSCT identified that the aortic annulus was commonly eccentric and often oval. This may in part explain the small, but clinically insignificant, differences in measured aortic annular diameters with other imaging modalities. MSCT after TAVR showed close proximity of both the prosthesis and displaced valvular calcium to the left main ostium in most patients. Neither eccentricity nor calcific deposits appeared to contribute significantly to severity of paravalvular regurgitation after TAVR.

Injection drug use and right sided endocarditis

If William Osler were alive today he would no doubt remark on the fundamental change in the nature of the disease that he originally described. Staphylococcal endocarditis in injection drug users is now the dominant form of the disease in many urban communities where there is a high incidence of injection drug use and homelessness. At our institution (a tertiary care, university affiliated hospital in inner Vancouver), 63% of 116 hospitalisations between 1994 and 2000 for infective endocarditis (IE) were in injection drug users. Right sided endocarditis accounts for 10% of all IE in population based surveys1 and a higher proportion of IE in injection drug users. Modern echocardiographic techniques have considerably augmented our ability to diagnose IE and to understand its natural history. Despite this, there are many areas in which our understanding of right sided IE remains incomplete. Right sided IE has a significant morbidity and mortality that adds a notable economic burden to stretched inner city health care facilities. The challenges of caring for this population of patients should not be underestimated and demands a logical and coordinated approach among care providers and physicians from a variety of specialties. This article reviews aspects of the epidemiology, clinical features, diagnosis, and treatment of right sided IE in injection drug users. Although right sided IE may occur in association with congenital heart disease and instrumentation of the right heart, it is overwhelmingly a disease of injection drug users, at least in western populations. Among injection drug users presenting with fever, 13% will have echocardiographic evidence of IE.2 If injection drug users with bacteraemia from an inner city demographic are considered, up to 41% will have evidence of IE.3 The pathogenic mechanisms that explain the increased prevalence of right sided IE in injection drug users are not …

Transcatheter Aortic Valve Replacement: Outcomes of Patients With Moderate or Severe Mitral Regurgitation

OBJECTIVES The aim of this study was to evaluate the impact of mitral regurgitation (MR) on outcomes after transcatheter aortic valve replacement (TAVR) and the impact of TAVR on MR. BACKGROUND Little is known of the influence of MR on outcomes after TAVR. METHODS The outcomes of patients with mild or less (n = 319), moderate (n = 89), and severe (n = 43) MR were evaluated after TAVR at 2 Canadian centers. RESULTS Patients with moderate or severe MR had a higher mortality rate than those with mild or less MR during the 30 days after TAVR (adjusted hazard ratio: 2.10; 95% confidence interval: 1.12 to 3.94; p = 0.02). However, the mortality rates after 30 days were similar (adjusted hazard ratio: 0.82; 95% confidence interval: 0.50 to 1.34; p = 0.42). One year after TAVR, moderate MR had improved in 58%, remained moderate in 17%, and worsened to severe in 1%, and 24% of patients had died. Severe MR had improved in 49% and remained severe in 16%, and 35% of patients had died. Multivariate predictors of improved MR at 1 year (vs. unchanged MR, worse MR, or death) were a mean transaortic gradient ≥ 40 mm Hg, functional (as opposed to structural) MR, the absence of pulmonary hypertension, and the absence of atrial fibrillation. CONCLUSIONS Moderate or severe MR in patients undergoing TAVR is associated with a higher early, but not late, mortality rate. At 1-year follow-up, MR was improved in 55% of patients with moderate or severe MR at baseline. Improvement was more likely in patients with high transaortic gradients, with functional MR, without pulmonary hypertension and without atrial fibrillation.

Transapical transcatheter aortic valve implantation: follow-up to 3 years.

BACKGROUND We performed the first human case of successful transapical transcatheter aortic valve implantation on a beating heart in October 2005, and therefore we have the longest follow-up on transapical aortic valve implantation in humans. We now report clinical and echocardiographic outcomes of transapical aortic valve implantation in 71 patients. METHODS Between October 2005 and February 2009, 71 patients (44 female) underwent transcatheter transapical aortic valve implantation with either 23- or 26-mm Edwards Lifesciences transcatheter bioprostheses. All patients with symptomatic aortic stenosis were declined for conventional aortic valve replacement owing to unacceptable operative risks and were not candidates for transfemoral aortic valve implantation because of poor arterial access. Clinical and echocardiographic follow-ups were performed before discharge, at 1 and 6 months, and then yearly. The mean follow-up was 12.9 +/- 11.5 months with a total of 917.3 months of follow-up. RESULTS Mean age was 80.0 +/- 8.1 years and predicted operative mortality was 34.5% +/- 20.4% by logistic EuroSCORE and 12.1% +/- 7.7% by The Society of Thoracic Surgeons Risk Calculator. Valves were successfully implanted in all patients. Twelve patients died within 30 days (30-day mortality: 16.9% in all patients, 33% in the first 15 patients, and 12.5% in the remainder), and 10 patients died subsequently. Overall survival at 24 and 36 months was 66.3% +/- 6.4% and 58.0% +/- 9.5%, respectively. Among 59 patients who survived at least 30 days, 24- and 36-month survivals were 79.8% +/- 6.4% and 69.8% +/- 10.9%, respectively. Late valve-related complications were rare. New York Heart Association functional class improved significantly from preoperative 3.3 +/- 0.8 to 1.8 +/- 0.8 at 24 months. The aortic valve area and mean gradient remained stable at 24 months (1.6 +/- 0.3 cm(2) and 10.3 +/- 5.9 mm Hg, respectively). CONCLUSION Our outcome suggests that transapical transcatheter aortic valve implantation provides sustained clinical and hemodynamic benefits for up to 36 months in selected high-risk patients with symptomatic severe aortic stenosis.

Transapical transcatheter aortic valve implantation: 1-year outcome in 26 patients

BACKGROUND We reported the first case of successful transapical transcatheter aortic valve implantation in a human subject in 2005 and have now completed a 12-month follow-up on our first 26 patients. This is, to date, the longest follow-up of patients undergoing transapical aortic valve implantation. METHODS Between October 2005 and January 2007, 26 patients (13 female) underwent transcatheter transapical aortic valve implantation with either 23- or 26-mm Edwards Lifesciences transcatheter bioprostheses. All patients with symptomatic aortic stenosis were declined for conventional aortic valve replacement because of unacceptable operative risks and were not candidates for transfemoral aortic valve implantation because of poor arterial access. Clinical and echocardiographic follow-up was performed before discharge and at 1, 6, and 12 months. Data from the 17 patients who survived over 12 months were used for comparisons of the baseline and follow-up results. RESULTS The mean age was 80 +/- 9 years, and the predicted operative mortality was 37% +/- 20% by using logistic EuroSCORE and 11% +/- 6% by using the Society of Thoracic Surgeons Risk Calculator. Valves were successfully implanted in all patients. Six patients died within 30 days (30-day mortality, 23%), and 3 patients died from noncardiovascular causes after 30 days (late mortality, 12%). Among patients who survived at least 30 days, 12-month survival was 85%. There were no late valve-related complications. New York Heart Association functional class improved significantly. The aortic valve area and mean gradient remained stable at 12 months (1.6 +/- 0.3 cm(2) and 9.6 +/- 4.8 mm Hg, respectively). CONCLUSION Our 1-year clinical and echocardiographic outcomes suggest that transapical transcatheter aortic valve implantation is a viable alternative to conventional aortic valve replacement in selected high-risk patients.

Percutaneous closure of an aortic prosthetic paravalvular leak with an Amplatzer duct occluder.

Following aortic valve replacement, up to 5% of patients may develop clinically significant paravalular leaks. Reoperation is associated with higher mortality and an excess risk of recurrent paravalvular insufficiency. No specifically designed transcatheter device is available for paravalular leak repair. We describe in a patient with severe aortic prosthetic paravalvular leak the use of an Amplatzer duct occluder device resulting in effective closure and symptomatic improvement.