Percutaneous transcatheter aortic valve implantation for degenerated surgical bioprostheses: the first case series in Asia with one-year follow-up.

INTRODUCTION: Percutaneous transcatheter aortic valve implantation (TAVI) has become an established therapy for inoperable and high-surgical-risk patients with severe aortic stenosis. Although TAVI in patients with degenerated surgical aortic bioprostheses (i.e. valve-in-valve TAVI) is increasingly reported in Western studies, such data is lacking in Asian patients. We describe the initial experience of valve-in-valve TAVI in Asia. METHODS: Eight patients who underwent valve-in-valve TAVI due to degenerated aortic bioprostheses were enrolled. The mechanism of bioprosthetic valve failure was stenotic, regurgitation or mixed. All procedures were performed via transfemoral arterial access, using the self-expanding CoreValve prosthesis or balloon-expandable SAPIEN XT prosthesis. RESULTS: The mean age of the patients was 71.6 ± 13.2 years and five were male. Mean duration to surgical bioprosthesis degeneration was 10.2 ± 4.1 years. Valve-in-valve TAVI was successfully performed in all patients. CoreValve and SAPIEN XT prostheses were used in six and two patients, respectively. There were no deaths, strokes or permanent pacemaker requirement at 30 days, with one noncardiac mortality at one year. All patients experienced New York Heart Association functional class improvement. Post-procedure mean pressure gradients were 20 ± 11 mmHg and 22 ± 8 mmHg at 30 days and one year, respectively. Residual aortic regurgitation (AR) of more than mild severity occurred in one patient at 30 days. At one year, only one patient had mild residual AR. CONCLUSION: In our experience of valve-in-valve TAVI, procedural success was achieved in all patients without adverse events at 30 days. Good clinical and haemodynamic outcomes were sustained at one year.

Abnormal origin of right coronary artery from left ventricle with bicuspid aortic stenosis.

Anomalous coronary arteries are rare but can lead to serious complications during cardiac operations if not recognized. We report a 55-year-old woman with anomalous origin of the right coronary artery from the left ventricle, and bicuspid aortic valve stenosis. Coronary angiography and computerized tomographic angiography indicated the diagnosis preoperatively. She underwent aortic valve replacement and coronary artery bypass grafting subsequently, with good recovery. One adult and two children with the same right coronary artery anomaly have been reported in the literature. Preoperative diagnosis is essential in these cases, and long-term follow-up is warranted.

Different expression of large-conductance calcium-activated K+ channels in human internal mammary and radial arteries.

AIMS: In this study, we investigated and compared the electrophysiological and molecular properties of large-conductance Ca(2+)-activated K(+) (BK(Ca)) channels between human internal mammary arteries (IMA) and radial arteries (RA). METHODS AND RESULTS: IMA and RA sections were obtained from 79 patients (including 9 females) undergoing coronary artery bypass graft surgery. We examined the effects of K(+) channel blockers tetraethylammonium (TEA), iberiotoxin (IBTX), and 4-aminopyridine (4-AP) on isolated smooth muscle cells (SMCs) using patch clamping. Both TEA (1 mM) and IBTX (0.1 µM) significantly decreased K(+) currents in IMA SMCs and RA SMCs, while 4-AP (1 mM) only had a weak effect. IBTX had a greater K(+)-blocking effect on IMA SMCs than on RA SMCs. Consistently, TEA and IBTX evoked significant constriction of both intact vascular rings. IBTX had a greater constrictor effect on IMA rings (18.5 ± 6.7%, n= 8) than on RA rings (10.6 ± 3.1%, n= 8), P< 0.05. RT-PCR and western blot analysis demonstrated that gene and protein expression of the α-subunit of BK(Ca) channels from IMA was greater than that from RA. CONCLUSION: The density of BK(Ca) channels is greater in human IMA than in RA resulting in greater BK(Ca) currents in SMCs from IMA. This may partly explain the finding of less spasm in IMA grafts than in RA grafts. Our results may be of value in determining the best anti-spasm agent to use peri-operatively.

How should I treat a percutaneous transcatheter mitral paravalvular leak closure?

BACKGROUND: A 49-year-old female presented with worsening exertional dyspnea (NYHA class III) and orthopnea for several months. Previous medical history was significant for rheumatic mitral regurgitation and three previous mitral valve replacements (MVRs). INVESTIGATION: Transesophageal echocardiography (TEE) revealed severe mitral paravalvular leak (PVL with two jets visualised. Cardiac computed tomography angiography (CTA) revealed a larger PVL and a smaller defect. DIAGNOSIS: Severe mitral paravalvular leak. TREATMENT: Transcatheter mitral paravalvular closure.

Absence of calcium channel alpha1C-subunit mutation in human atrial fibrillation.

L-type voltage-gated calcium channel mutation or phenotypical variation resulting from alternative splicing has been associated with sudden arrhythmogenic death and heart failure. Changes in calcium current density, protein and mRNA expression have been associated with atrial fibrillation. We studied human atrium harvested from 16 cardiac surgery patients (coronary bypass and/or valve procedures) for mutation of Ca(v)1.2 alpha(1C) (the main pore-forming subunit of L-type voltage-gated calcium channel) for an association with atrial fibrillation. Seven patients had persistent atrial fibrillation and one was resuscitated from ventricular arrhythmia. Clinical data were collected and prospectively updated for the development of arrhythmia. Four (25%) patients had new-onset postoperative paroxysmal atrial fibrillation. DNA from all atrial specimens was amplified, extracted, and sequenced. The alpha(1C)-subunit mutation was absent in all specimens obtained from all patients, regardless of heart rhythm. This suggests that atrial fibrillation is not associated with loss-of-function mutation of the main pore-forming subunit of the L-type voltage-gated calcium channel.

Paradoxical orthodeoxia in a patient with a large thoracic aortic aneurysm.

INTRODUCTION: Orthodeoxia is a rare clinical syndrome characterised by dyspnoea and arterial deoxygenation that accompanies a change from a supine to erect position. CLINICAL PICTURE: We describe an unusual case of "paradoxical orthodeoxia" in a 70-year-old man with a thoracic aortic aneurysm: arterial desaturation when supine that improved when erect. TREATMENT AND OUTCOME: Non-invasive imaging revealed compression of the left pulmonary artery by the aneurysm (thoracic computed tomography) and patent foramen ovale (transesophageal echocardiography). Nuclear studies show decreased relative left lung perfusion attributable to the former, and right-to-left atrial shunt attributable to the latter. The degree of right-to-left shunt increases in the supine position: nuclear pulmonary shunt study shows shunt extent of 21% when supine versus 10% erect. CONCLUSION: A physioanatomical explanation is proposed.

Primary pulmonary sarcomatoid carcinoma with intracardiac extension.

Primary pulmonary sarcomatoid carcinoma is rare. It is generally regarded as an aggressive tumor. We report, to our best knowledge, the first case of pulmonary sarcomatoid carcinoma with extensive intracardiac spread. This case illustrated the misleading clinical features of this condition. Previous literature is also reviewed.

Coronary-pulmonary arteriovenous fistula used as proximal anastomotic site for saphenous vein grafts in patient with porcelain aorta.

Coronary artery bypass grafting in patients with porcelain aorta and calcified great vessels is associated with a high risk of systemic embolism. Various techniques have been suggested to minimize that risk. We describe the case of a patient with left main coronary disease and a severely calcified ascending aorta, who could not undergo cardiopulmonary bypass. To the best of our knowledge, this is the 1st reported use of a congenital coronary-pulmonary arteriovenous fistula as a proximal anastomotic site for saphenous vein grafts, to achieve optimal revascularization in a patient with porcelain aorta.