Allograft Heart Valves: Current Aspects and Future Applications.

Human heart valve allografts continue to represent almost perfect substitutes for heart valves. They have optimal hemodynamic characteristics and are highly resistant to infections. The first clinical use of allograft heart valves was as homovitals being transplanted after antibiotic incubation without any preservation. Since 1968, relatively standardized frozen cryopreservation (SFC) has been employed, including storage in vapor-phase liquid nitrogen. Disadvantages, particularly in pediatric patients, are limited availability due to organ scarcity, inability to grow, degeneration, immune response, and long-term failure. However, in contrast to alternative prosthetic or bioprosthetic heart valve replacements, they represent the best pediatric and juvenile replacement options for the pulmonary valve. Application of multiphoton imaging analysis for three-dimensional visualization of elastin and collagen by induction of autofluorescence without chemical fixation, embedding, and staining has revealed partial destruction of elastic and collagenous matrix in SFC valves. As the overall amount of collagen and elastin remains unchanged, the observed destruction is attributed to freezing-induced extracellular matrix damages due to ice crystal formation during SFC. The objective of this review is an assessment of current allograft preservation methods and the potential of novel preservation techniques to avoid ice formation with accompanied better long-term function.

Bridge to recovery or permanent system implantation: an eight-year single-center experience in transvenous semipermanent pacing.

BACKGROUND: To compare the risks, implications, and outcomes of transvenous semipermanent pacing as a bridge to permanent system implantation or recovery. METHODS: We investigated semipermanent transvenous pacing systems consisting of one (n = 57%) or two (n = 3%) bipolar active-fixation pacing leads and an attached epicutaneous pulse generator implanted from 2000 to 2009. The study population comprised 60 patients aged 72.9 ± 10.5 years (44 [73.3%] male). Forty-two (70%) were enrolled for complete system explantation for cardiac-implanted electronic devices associated infection. Eighteen (30%) required temporary pacing in the context of a variety of mostly severe cardiac and noncardiac conditions. The semipermanent pacing systems were removed after implantation of permanent systems or recovery of a noncompromising heart rhythm, respectively. RESULTS: Transvenous semipermanent lead implantation was successful in 59 (98.3%) patients. Major and minor intraoperative complications occurred in one case (1.7%) each. The semipermanent systems were left in situ for a mean period of 14.6 ± 8.1 days). They served as a bridge to permanent system implantation in 68.3% (n = 41) and as a bridge to recovery of a noncompromising heart rhythm in 11.7% (n = 7). Four patients (8.3%) died with the semipermanent pacing system in situ, and seven (11.7%) were transferred to external hospitals with semipermanent pacing systems. CONCLUSIONS: Transvenous semipermanent pacing with bipolar active-fixation leads and epicutaneous pulse generators provide an important option for prolonged temporary pacing as a bridge to permanent system implantation or recovery.

Application of intravascular dissection devices for closed chest coronary sinus lead extraction: an interdisciplinary approach.

BACKGROUND: Increasing application of cardiac resynchronization therapy is accompanied by an increase in patients requiring removal of coronary sinus (CS) leads. The aim of this study was to determine outcomes of closed chest CS lead extraction using intravascular dissection devices. METHODS: Between 2000 and 2011, 41 patients (80.5% men; aged 64.2±13.8 years) underwent transvenous CS lead extraction procedures. Reasons for lead extraction were infection in 9, CS lead dislodgement in 15, lead malfunction, including manufacturer-initiated product recall in 6, phrenic nerve stimulation in 5, combinations of causes in 5, and elective extraction concomitant with generator replacement for battery depletion in 1. RESULTS: In addition to 24 isolated CS lead extractions, we performed 17 multiple lead extractions (2 to 4 leads) after a mean of 30.6±32.5 months. The time elapsed from implantation was 4.6±9.1 months for isolated CS and 42.6±32.4 months for multiple lead extractions. Extraction by direct manual traction was feasible in 13 patients by locking stylets in 6. Escalation to mechanical sheaths was required in 17 patients and to electrosurgical sheaths in 5. More aggressive methods were associated with longer implantation times and positive infection status. No deaths or major periprocedural complications occurred. Six minor postprocedural complications, of which three were surgically related, occurred in 5 patients. CONCLUSIONS: Closed chest CS lead extraction can be safely performed with excellent results. We recommend an escalating approach from isolated manual traction over locking stylets to mechanical sheaths and, eventually, electrosurgical dissection devices. The application in mainly high-risk patients demands an interdisciplinary approach to enhance safety and limit morbidity and death.

Endovascular repair of acute symptomatic pararenal aortic aneurysm with three chimney and one periscope graft for complete visceral artery revascularization.

PURPOSE: To describe a modified endovascular technique for complete revascularization of visceral and renal arteries in symptomatic pararenal aortic aneurysm (PRAA). TECHNIQUE: Arterial access was surgically established in both common femoral arteries (CFAs) and the left subclavian artery (LSA). Revascularization of the left renal artery, the celiac trunk, and the superior mesenteric artery was performed through one single sheath via the LSA. Suitable covered stents were put in the aortic branches but not deployed. The right renal artery was accessed over the left CFA. Due to the longitudinal extension of the presented aneurysm two stent-grafts were introduced via the right CFA. After deploying the aortic stent-grafts, all covered stents in the side branches were deployed consecutively with a minimum overlap of 5 mm over the cranial and caudal stent-graft edges. Simultaneous ballooning was performed to fully expand all stent-grafts and warranty patency. CONCLUSION: This is the first report in the literature of chimney grafting in PRAA for complete revascularization of visceral and renal branches by using more than two covered stents introduced from one side through one single sheath. However this technique is modified, it should be used only in bailout situations when branched stent-grafts are not available and/or surgery is not suitable.

Stent-assisted embolization as "bailout" option in aortic aneurysm.

The authors report two cases of stent-assisted embolization (SAE) in the aorta. In one case, SAE was performed for treatment of a pseudoaneurysm; the procedure consisted of stent placement and embolization with an AMPLATZER Vascular Plug and detachable coils through the stent struts. In the second case, SAE was performed to stop acute bleeding from an aortoureteral fistula. Before SAE in this case, the aortic bifurcation was reconstructed with self-expandable and balloon-expandable stents. SAE was technically successful in both cases. SAE for aortic pathologic processes may be useful in selected cases as an alternative to surgery or endovascular stent-graft therapy.

Endovascular aneurysm repair using a reverse chimney technique in a patient with Marfan syndrome and contained ruptured chronic type B dissection.

We report endovascular thoracic and abdominal aneurysm repair (EVAR) with reverse chimney technique in a patient with contained ruptured type B dissection. EVAR seems feasible as a bailout option in Marfan patients with acute life-threatening disease.