Permanent pacemaker implantation after transapical transcatheter aortic valve implantation

The aim of the study was to determine the incidence of permanent pacemaker implantation (PPMI) in a cohort of 358 patients undergoing transapical aortic valve implantation (TAVI) using a balloon-expandable prosthesis between April 2008 and March 2011. After excluding patients who had had a previous PPMI (n=36; 10%), the study group consisted of 322 patients. These were divided into two groups: patients who required PPMI (PPM group) and patients who did not require it (non-PPM group). Preoperative, perioperative and one-year follow-up data were collected prospectively. Twenty (6.2%) patients required PPMI. Previous implantation of an aortic prosthesis (P=non-significant), previous coronary artery bypass grafting (P=0.05) and coronary artery disease (P<0.005) were more common in the non-PPM group. On logistic regression, only patient age seemed to be correlated to PPMI (P=0.05, odds ratio 1.08; CI 0.9-1.1). There was no difference in survival rate between the groups after 30?days (PPM group 95%, non-PPM group 93.6%). Similarly, the survival rate did not differ after one year (PPM group 84%, non-PPM group 80.9%; P=0.3). The PPMI rate after transapical TAVI using a balloon-expandable prosthesis is thus low, and has no impact on early and follow-up mortality.     

Promoter methylation of Wnt antagonists DKK1 and SFRP1 is associated with opposing tumor subtypes in two large populations of colorectal cancer patients

Aberrant activation of canonical Wnt signaling is a hallmark event in colorectal carcinogenesis. The Dickkopf-1 (DKK1) and Secreted Frizzled Related Protein 1 (SFRP1) genes encode extracellular inhibitors of Wnt signaling that are frequently silenced by promoter hypermethylation in colorectal cancer (CRC). These methylation events have been identified as prognostic markers of patient outcome and tumor subtype in several cancers but similar roles in CRC have not been comprehensively examined. In CRC, the microsatellite instability (MSI) subtype associates with favorable disease outcome but the molecular events that are responsible remain poorly understood. Consequently, we quantified promoter methylation status of the Wnt antagonist genes DKK1 and SFRP1 in a large population-based cohort of CRCs from Ontario (n = 549) and Newfoundland (n = 696) stratified by MSI status. We examined the association between methylation status and clinicopathological features including tumor MSI status and patient survival. DKK1 and SFRP1 were methylated in 13 and 95% of CRCs, respectively. In Ontario, DKK1 methylation was strongly associated with MSI tumors after adjustment for age, sex and tumor location [odds ratio (OR) = 13.7, 95% confidence interval (CI) = 7.8-24.2, P < 0.001]. Conversely, SFRP1 methylation was inversely associated with MSI tumors after these adjustments (OR = 0.3, 95% CI = 0.1-0.9, P = 0.009). Similar results were obtained in Newfoundland. There were no independent associations with recurrence-free survival. This is the first large study to identify associations between Wnt antagonist promoter hypermethylation and CRC MSI subtype. These events provide insight into subtype-specific epigenetic mediation of Wnt signaling in CRC.     

Contrast magnetic resonance imaging diagnosis of periaortic bronchogenic cyst

A 39-year-old woman who had suffered from intermittent left back pain for 7 months was diagnosed as having a tumor in the posterior mediastinum to the left of the seventh thoracic vertebra. It was attached to the descending aorta and to a rib. Preoperative contrast magnetic resonance imaging strongly suggested that the tumor was a cystic lesion. We resected the tumor, and it was revealed to be a bronchogenic cyst. After 7 months' follow-up, the patient is asymptomatic and without complications. Bronchogenic cysts are rare developmental abnormalities of the primitive foregut and seldom arise in the posterior mediastinum, especially in a periaortic position. The preoperative diagnosis is difficult because of the diverse nature of a cyst's contents. We were able to predict preoperatively the nature of the tumor and its relation to other structures. Contrast magnetic resonance imaging is helpful in elucidating these cysts.     

Surgical treatment of right-sided active infective endocarditis with or without involvement of the left heart: 20-year single center experience.

OBJECTIVE: The aim of this paper is to review the 20-year experience of surgical treatment of right-sided infective endocarditis at our institution, and in particular to compare the outcome of isolated right-sided endocarditis to right-sided endocarditis with involvement of the left heart. METHODS: Between April 1986 and April 2006, 84 operations had to be performed in 79 patients (49 men, median age 43.5 years). There were 72 (85.7%) cases of native and 12 (14.3%) of prosthetic valve endocarditis. In 57 (67.9%) cases, operation was for isolated right-sided endocarditis (RSE) and in 27 (32.1%) cases for combined right and left-sided endocarditis (RLSE). Follow-up was completed in all 91% of survivors. The median follow-up time at 448 patient years was 3.59 years (range 6 months-19.27 years). RESULTS: There was a highly significant difference between the survival rates of patients operated on due to RSE compared to RLSE: the 30-day, 1-, 5-, 10- and 20-year survival rate after RSE operation was 96.2%, 88.4%, 73.5%, 70.4% and 70.4%, respectively, compared to 72.0%, 67.8%, 50.8%, 35.6% and 35.6% after operation for RLSE (p=0.0093). Patients with RLSE more often underwent emergency operations (p<0.001), preoperatively were more often on high-dose catecholamines (p<0.006) and intraoperatively showed more abscess formation (p<0.001). Freedom from reoperation at 30 days, 1-, 5-, 10- and 20-year was 97.4%, 95.9%, 92.2%, 88.6% and 88.6%, respectively. Risk factors for early mortality were priority of surgery with an odds ratio (OR) of 5.13, age over 40 years (OR 1.04 and 3.24) and left heart involvement (or 2.54). CONCLUSIONS: Our surgical strategy for right-sided infective endocarditis is based on three principles: (1) debridement of the infected area or vegetectomy; (2) valve repair whenever possible, avoiding artificial material; (3) if valve replacement is unavoidable, use of a biological substitute without any artificial material that might become infected. Following these strategies surgery of right-sided infective endocarditis with or without left-side involvement can be performed with good early, mid-term and long-term results. Patients with involvement of the left side showed not only worse preoperative conditions but also a significantly poorer clinical outcome than those with isolated right-sided infective endocarditis.     

First experiences with a novel magnetically suspended axial flow left ventricular assist device

Axial flow pumps have gained increased acceptance since their first clinical use in 1998. The present report summarizes the clinical experience with patients treated for severe cardiogenic shock for the first time with a newly developed axial flow pump with magnetically levitated bearings. Material and methods: The axial flow pump Incor was implanted in 24 patients between June 2002 and June 2003. All except one patient were men. In 16 patients dilative cardiomyopathy, in seven ischemic and in one restrictive cardiomypathy had been diagnosed. All patients presented with catecholamine-dependent end-stage heart failure, seven of them were on an artificial ventilator and three were dependent on intraaortic balloon pump support. All patients suffered from organ dysfunction resulting from low cardiac output. Results: There were no perioperative deaths. The 30-day mortality rate was 8% (n=2); 79% (n=19) of patients reached a condition to be discharged home. The cumulative time on the device is 6.9 years; the longest individual time up to July 1, 2003 is 12.6 months. There were no structural defects or failures of the system. In one case the controller had to be exchanged because of intermittent malfunction. Cardiac output ranged between 4 and 6 l in all instances and there were no cases of infection of the drive-line or the system. Hemolysis was present initially but was not detectable in the later course. There were three instances of transient ischemic attacks. Two patients developed late cardiac tamponade with re-opening of the chest after 9 and 14 days. In one patient persistent gastrointestinal bleeding required re-hospitalization and transfusion therapy. Two patients were weaned from the device after 6 and 7 months of support, respectively. Conclusion: The preliminary clinical experience with Incor is promising. The flow is sufficient for recovery from multiorgan failure and the pump allows long-term hemolysis-free support. The concept of magnetically levitated bearings has proven to be durable and reliable. In the case that the heart may recover through unloading, weaning from the pump is possible.