Derek Chin

Predictors for permanent pacemaker requirement after transcatheter aortic valve implantation with the CoreValve bioprosthesis.

INTRODUCTION Changes in atrioventricular (AV) conduction and need for permanent pacemaker (PPM) are a recognized complication after open aortic valve replacement. We hypothesized that the need for PPM after CoreValve (Corevalve Inc, Irvine, CA) can be predicted with a combination of baseline variables. METHODS In patients undergoing transcatheter aortic valve implantation, potential clinical, electrocardiographic and echocardiographic predictors of permanent pacing requirement were studied. RESULTS Between January 2007 and March 2008, 34 patients with severe symptomatic aortic stenosis were recruited in a single center. Mean age was 84.4 years (SD 5.4, range 71-93). Of 34 cases paced at baseline, 3 (8.8%) were excluded from this analysis, as was the single periprocedural mortality. Of the remaining 30, 10 underwent permanent pacemaker implantation during the same admission (33.3%). PPM was for prolonged high-grade AV block in 4 cases, episodic high-grade AV block in 5, and sinus node disease in 1. Need for pacemaker was correlated to left axis deviation at baseline (P = .004, r = 0.508) and left bundle-branch block with left axis deviation (P = .002, r = 0.548). It was related to diastolic interventricular septal dimension on transthoracic echocardiography >17 mm (P = .045, r = 0.39) and the baseline thickness of the native noncoronary cusp (P = .002, r = 0.655). A susceptibility model was generated, and if at least one of (1) left bundle-branch block with left axis deviation, (2) interventricular septal dimension >17 mm, or (3) noncoronary cusp thickness >8 mm was present, the likelihood of PPM could be predicted with 75% sensitivity and 100% specificity and a receiver operating characteristic curve area of 0.93 +/- 0.055 (P < .001). CONCLUSIONS After transcatheter aortic valve implantation with CoreValve, permanent pacing was performed in around a third of patients and we present preliminary concepts towards a predictive model for this phenomenon.

Autotransplantation of unmanipulated bone marrow into scarred myocardium is safe and enhances cardiac function in humans.

Stem cell transplants into damaged myocardium may have the potential to improve cardiac function. We investigated the safety of transplanting unmanipulated autologous bone marrow into infarcted myocardium of patients undergoing coronary bypass surgery and assessed its efficacy to improve cardiac function. Fourteen patients with one or more areas of transmural myocardial infarction were studied. Autologous bone marrow was obtained by sternal bone aspirate at the time of surgery, diluted in autologous serum at a ratio of 1:2, and then injected 1 cm apart into the mid-depth of the left ventricular scar. There were no deaths, no perioperative myocardial infarctions, and no significant ventricular arrhythmias. Dobutamine stress echocardiography demonstrated overall improvement in the global and regional left ventricular function 6 weeks and 10 months after surgery. Of 34 infarcted left ventricular segments, 11 were injected with bone marrow alone, 13 were revascularized with a bypass graft alone, and 10 received bone marrow transplantation and a bypass graft in combination. Only the left ventricle segmental wall motion score of the areas injected with bone marrow and receiving a bypass graft in combination improved at low dose and at peak dobutamine stress. These findings suggest that transplantation of unmanipulated autologous bone marrow into scar tissue of the human heart is safe and enhances cardiac function only when used in combination with myocardial revascularization. This benefit can be seen after 6 weeks of the bone marrow transplant and is maintained after 10 months of follow-up.

Prosthesis-patient mismatch after transcatheter aortic valve implantation with the Medtronic-Corevalve bioprosthesis

AIMS Prosthesis-patient mismatch (P-PM) is an important determinant of morbidity and mortality following open aortic valve replacement. The aims of this study were to report its incidence and determinants following transcatheter aortic valve implantation (TAVI) with the Corevalve bioprosthesis, which have-thus far-not been described. METHODS AND RESULTS Patients with severe calcific aortic stenosis received TAVI with the Corevalve bioprosthesis via transfemoral route. Following TAVI, moderate P-PM was defined as indexed aortic valve effective orifice area (AVAi) < or =0.85 cm(2)/m(2) and severe P-PM as AVAi < or =0.65 cm(2)/m(2). Clinical, echocardiographic, and procedural factors relating to P-PM were studied. Optimal device position was defined on fluoroscopy as final position of the proximal aspect of the Corevalve stent frame 5-10 mm below the native aortic annulus. Between January 2007 and January 2009, 50 consecutive patients underwent TAVI in a single centre with the Corevalve bioprosthesis. Mean age was 82.8 years (SD 5.9; 70-93) and 48% were male. P-PM occurred in 16 of 50 cases (32%). Optimal position was achieved in 50% of cases. P-PM was unrelated to age, annulus size, LVOT size, Corevalve size, aortic angulation, ejection fraction, and sex. It was inversely correlated to optimal position (Spearman rho r = -0.34, P = 0.015). Those with optimal positioning had a 16% incidence of P-PM relative to 48% of those with suboptimal positioning (Pearson chi(2) P = 0.015). CONCLUSION The incidence of P-PM following TAVI with the Corevalve bioprosthesis is compared favourably with that seen after AVR with conventional open stented bioprostheses and its occurrence is influenced by device positioning.

Echocardiography for transcatheter aortic valve implantation.

Transcatheter aortic valve implantation (TAVI) is a new technology that treats severe aortic stenosis. The technology has specific and mandatory technical requirements that must be met to allow safe and successful procedures. The echocardiographic method for diagnosis of aortic stenosis, anatomical case selection, procedural guidance and management of complications is discussed in this context. The role of the imaging specialist is defined within the TAVI team aiming to provide good outcomes for this high risk cohort of patients.

Randomized, controlled trial of intramuscular or intracoronary injection of autologous bone marrow cells into scarred myocardium during CABG versus CABG alone

Background Studies of the transplantation of autologous bone marrow cells (BMCs) in patients with chronic ischemic heart disease have assessed effects on viable, peri-infarct tissue. We conducted a single-blinded, randomized, controlled study to investigate whether intramuscular or intracoronary administration of BMCs into nonviable scarred myocardium during CABG improves contractile function of scar segments compared with CABG alone.Methods Elective CABG patients (n = 63), with established myocardial scars diagnosed as akinetic or dyskinetic segments by dobutamine stress echocardiography and confirmed at surgery, were randomly assigned CABG alone (control) or CABG with intramuscular or intracoronary administration of BMCs. The BMCs, which were obtained at the time of surgery, were injected into the mid-depth of the scar in the intramuscular group or via the graft conduit supplying the scar in the intracoronary group. Contractile function was assessed in scar segments by dobutamine stress echocardiography before and 6 months after treatment.Results The proportion of patients showing improved wall motion in at least one scar segment after BMC treatment was not different to that observed in the control group (P = 0.092). Quantitatively, systolic fractional thickening in scar segments did not improve with BMC administration. Furthermore, BMCs did not improve scar transmurality, infarct volume, left ventricular volume, or ejection fraction.Conclusion Injection of autologous BMCs directly into the scar or into the artery supplying the scar is safe but does not improve contractility of nonviable scarred myocardium, reduce scar size, or improve left ventricular function more than CABG alone.

Identification of previously undiagnosed left ventricular systolic dysfunction: Community screening using natriuretic peptides and electrocardiography

Aims: We examined strategies to improve the positive predictive value of natriuretic peptides in screening for undiagnosed left ventricular systolic dysfunction (LVSD) in the community. Methods and results: The value of B‐type(BNP), N‐terminal proB‐type (N‐BNP) and N‐terminal proAtrial(N‐ANP) natriuretic peptides was prospectively assessed in 1360 subjects (45–80 years) together with echocardiography and electrocardiography. Seventeen individuals had definite and 13 had borderline, LVSD. Receiver‐operating‐characteristic (ROC) curve analysis showed the superiority of BNP (ROC areas 0.942 for definite LVSD, P<0.03; 0.934 for borderline LVSD, P<0.003) compared to N‐BNP or N‐ANP. Peptide levels, major ECG abnormality and ischaemic heart disease (IHD) history were independent predictors of LVSD. Logistic regression modelling incorporating these factors improved ROC areas for all natriuretic peptides. The specificity of all natriuretic peptides is enhanced by consideration of these factors. Conclusions: In population screening for definite LVSD, consideration of plasma natriuretic peptide levels together with the presence of major ECG abnormalities and IHD history reduces by a factor of six (in comparison to consideration of plasma natriuretic peptide levels in isolation) the number of subjects requiring echocardiography to detect one case of LVSD (for BNP, 44 falling to seven). Similar improvements were evident for N‐ANP and N‐BNP. Inclusion of major ECG abnormalities and IHD history improves the performance of any natriuretic peptide used in screening programmes for ruling in undiagnosed LVSD.

Decrease of pulmonary hypertension impacts on prognosis after transcatheter aortic valve replacement.

AIMS Transcatheter aortic valve replacement (TAVR) is established as a treatment strategy for patients with end-stage aortic stenosis, many of whom are suffering from severe pulmonary hypertension (PH). In cardiac surgery patients, PH is associated with less symptomatic improvement and increased late mortality. This study elucidates the impact of PH on outcome after TAVR. METHODS AND RESULTS Pre and 90 days post-TAVR, pulmonary artery systolic pressure (PASP) was determined non-invasively by echocardiography in 353 patients undergoing TAVR. PH was classified as absent (<30 mmHg), mild-to-moderate (30-60 mmHg), and severe (>60 mmHg). Three hundred and fifty-three patients at high surgical risk, indicated by a logistic EuroSCORE of 26.6±16.5%, underwent TAVR. The severity of PH before TAVR was related to outcome with two-year mortality rates of 13.9%, 27.3%, and 48.4% for PASP <30 mmHg, 30-60 mmHg, and >60 mmHg, respectively (p=0.001). In patients with baseline PASP >60 mmHg, PASP decreased from 65.6±7.6 mmHg to 49.5±14.0 mmHg (p<0.001) at 90 days after TAVR. Patients with persistent severe PH had a worse prognosis than patients with a decrease of PASP below 60 mmHg (two-year mortality rate: 50.0% vs. 18.6%; p=0.001). CONCLUSIONS Severe pulmonary hypertension predicts adverse outcome after TAVR. Reduction of PASP after the procedure is associated with favourable prognosis.

Video‐Assisted Thoracoscopic Implantation of the Left Ventricular Pacing Lead for Cardiac Resynchronization Therapy

Background: To study the feasibility and efficacy of video‐assisted thoracoscopic (VAT) placement of the left ventricular pacing lead for cardiac resynchronization therapy (CRT) where the conventional transvenous coronary sinus approach has failed.

Anatomic suitability for present and next generation transcatheter aortic valve prostheses: evidence for a complementary multidevice approach to treatment.

OBJECTIVES This study sought to assess the proportion of patients anatomically suitable for transcatheter aortic valve implantation by multiple access approaches. BACKGROUND The devices currently in mainstream use for transcatheter treatment of severe aortic stenosis are those of Edwards (Edwards Lifesciences, Nyon, Switzerland) and Medtronic CoreValve (M-C) (Luxembourg City, Luxembourg). The range of patients that these can presently treat requires elucidation to guide the necessary evolution of these technologies and increase their scope of therapy. METHODS A consecutive series of patients were assessed with transthoracic or transesophageal echocardiography and invasive angiography to assess anatomical suitability by different approaches. The transfemoral access requirements for Edwards and M-C (Edwards currently 22- and 24-F, soon to be 18- and 19-F; M-C 18-F) as well as the aortic valve annular criteria (18 to 25 mm and 20 to 27 mm, respectively) were incorporated in this assessment. Patients unsuitable for the transfemoral approach were considered for Edwards transapical and M-C transaxillary and direct ascending aortic access. Patients suitable for these devices and access approaches were identified. RESULTS Data were analyzed for 100 consecutive patients. Edwards suitability was 28% for Edwards-Sapien transfemoral, 78% for Edwards Novaflex transfemoral, and 88% for Edwards-Sapien transapical. Medtronic CoreValve suitability was 84% for transfemoral and 89% using additional transaxillary and direct aortic approaches. Of the 12 patients unsuitable for Edwards-based procedures, 8 were suitable for M-C. Of the 11 patients unsuitable for M-C-based techniques, 8 were suitable for Edwards. Only 3% were anatomically unsuitable for all approaches. CONCLUSIONS In this series, 97% of patients were anatomically suitable for a complementary approach to treatment.

Comparison of Complete Versus Incomplete Stent Frame Expansion After Transcatheter Aortic Valve Implantation With Medtronic CoreValve Bioprosthesis

We sought to determine the significance of incomplete stent frame expansion after transcatheter aortic valve implantation with the Medtronic-CoreValve device. Incomplete coronary stent expansion is a well-described phenomenon. Transcatheter valves are mounted on stents; however, the incidence of incomplete stent expansion after transcatheter aortic valve implantation, its sequelae and predictors are poorly elucidated. The 18Fr CoreValve revalving system was used to treat anatomically and clinically suitable patients with severe calcific aortic stenosis. The postdeployment stent dimensions were measured on fluoroscopic images at multiple levels of the stent frame. Incomplete expansion at each was defined as <100% expected and complete expansion as ≥100%. These parameters were correlated to the hemodynamic and clinical end points. A total of 50 consecutive patients underwent transcatheter aortic valve implantation with the Medtronic-CoreValve at a single center from January 2007 to December 2008. For the inflow portion, incomplete expansion was seen in 54% of patients and was unrelated to the aortic valve area, peak or mean aortic valve gradients, or measures of aortic regurgitation, although it was paradoxically associated with a lower incidence of prosthesis-patient mismatch. Incomplete expansion of the constrained portion was seen in 62% of the patients and displayed a trend toward a greater incidence of aortic regurgitation grade 2 or greater, although this was rare. Incomplete expansion of the Medtronic CoreValve stent frame is common. For the most part, valvular hemodynamic function was satisfactory, regardless of the degree of expansion of the stent frame that carries it and a strategy of reluctant postdilation in the context of incomplete stent frame expansion was supported.