Long-term results of autologous scaffold-free tissue-engineered vascular graft for hemodialysis access.

BACKGROUND: The growing size of the end stage renal disease (ESRD) population highlights the need for effective dialysis access. Exhausted native vascular access options have led to increased use of catheters and prosthetic shunts, which are both associated with high risks of access failure and infection. Emerging alternatives include tissue-engineered vascular grafts (TEVG). Here we present the endpoint results for 10 ESRD patients with the scaffold-free tissue-engineered vascular access produced from sheets of extracellular matrix produced in vitro by human cells in culture. METHODS: Grafts were implanted as arteriovenous shunts in 10 ESRD patients with a complex history of access failure. Follow-up included ultrasound control of graft morphology and function, dialysis efficiency, access failure, intervention rate, as well as immunohistochemical analysis of graft structure. RESULTS: One patient died of unrelated causes and three shunts failed to become useable access grafts during the 3-month maturation phase. The 12-month primary and secondary patency for the other six shunts was 86%. Survival of six shunts functioning as the vascular access was 22 ± 12 months with longest primary patency of 38.6 months. The dialysis event rate of 3.34 per patient-year decreased significantly with the use of this TEVG to 0.67. CONCLUSIONS: This living autologous tissue-engineered vascular graft seems to be an alternative to synthetic vascular access options, exhibiting advantages of native arteriovenous fistula.

Effectiveness of haemodialysis access with an autologous tissue-engineered vascular graft: a multicentre cohort study.

BACKGROUND: Application of a tissue-engineered vascular graft for small-diameter vascular reconstruction has been a long awaited and much anticipated advance for vascular surgery. We report results after a minimum of 6 months of follow-up for the first ten patients implanted with a completely biological and autologous tissue-engineered vascular graft. METHODS: Ten patients with end-stage renal disease who had been receiving haemodialysis through an access graft that had a high probability of failure, and had had at least one previous access failure, were enrolled from centres in Argentina and Poland between September, 2004, and April, 2007. Completely autologous tissue-engineered vascular grafts were grown in culture supplemented with bovine serum, implanted as arteriovenous shunts, and assessed for both mechanical stability during the safety phase (0-3 months) and effectiveness after haemodialysis was started. FINDINGS: Three grafts failed within the safety phase, which is consistent with failure rates expected for this high-risk patient population. One patient was withdrawn from the study because of severe gastrointestinal bleeding shortly before implantation, and another died of unrelated causes during the safety period with a patent graft. The remaining five patients had grafts functioning for haemodialysis 6-20 months after implantation, and a total of 68 patient-months of patency. In these five patients, only one intervention (surgical correction) was needed to maintain secondary patency. Overall, primary patency was maintained in seven (78%) of the remaining nine patients 1 month after implantation and five (60%) of the remaining eight patients 6 months after implantation. INTERPRETATION: Our proportion of primary patency in this high-risk cohort approaches Dialysis Outcomes Quality Initiative objectives (76% of patients 3 months after implantation) for arteriovenous fistulas, averaged across all patient populations.

Transendocardial autologous bone marrow in chronic myocardial infarction using a helical needle catheter: 1-year follow-up in an open-label, nonrandomized, single-center pilot study (the TABMMI study).

BACKGROUND: Cell therapy has shown benefit in preclinical and clinical studies, although debate continues on the mechanism of action and the most appropriate methods for performing such therapies. We assessed the hypothesis that helical needle transendocardial (TE) delivery of autologous bone marrow (ABM) mononuclear cells around regions of hypo- or akinesia in patients after chronic myocardial infarction (MI) would be safe and possibly improve ejection fraction (EF). METHODS AND RESULTS: Ten stable post-MI patients with an EF <40% were enrolled. Autologous bone marrow cells were aspirated from the iliac crest and delivered percutaneously with a TE helical needle catheter. A total of 86 x 10(6) cells were injected into 7.1 +/- 3.1 sites around the infarct to target the peri-infarct zones. Two-dimensional echocardiographic left ventricle EF measurements, 24-hour Holter, and exercise tolerance testing were performed at baseline, day of procedure, 1 and 12 weeks, and 6 and 12 months. There were no adverse events associated with the catheter-based cell transplantation procedure. At 6 and 12 months, all patients showed an improvement in left ventricle EF over baseline (35.2 +/- 4.6 to 40.8 +/- 4.5, P = .003 at 6 months; 35.2 +/- 4.6 to 42.3 +/- 5.1, P = .0001 at 12 months). CONCLUSIONS: Autologous bone marrow cells delivered with the helical needle TE catheter was safe in this small uncontrolled study in patients with chronic MI. Increased EF and other positive data trends support continued development of this therapeutic strategy in larger controlled trials.

[Stenting of right coronary artery arising from the left sinus of Valsalva]. / Stent en la arteria coronaria derecha con origen anómalo en el seno de Valsalva izquierdo.

We report the stenting of a long lesion situated in an anomalous right dominant coronary artery arising from the left sinus of Valsalva. The patient was referred to our unit with a diagnosis of progressive angina and no other cardiopathy. We emphasize the convenience of having a good arrangement of the guiding-catheter with the original and the initial course of the artery, and also having a suitable support for the treatment programmed.

Transendocardial autologous bone marrow in myocardial infarction induced heart failure, two-year follow-up in an open-label phase I safety study (the TABMMI study).

AIMS: To assess the hypothesis that fluoroscopically-guided helical needle transendocardial delivery of autologous bone marrow (ABM) mononuclear cells (MNCs) in chronic post myocardial infarction patients is safe and improves ejection fraction (EF). METHODS AND RESULTS: Twenty ischaemic heart failure patients with an EF ≤40% were enrolled. ABMMNCs were prepared, counted for CD34+ and CD133+ content, and delivered percutaneously to the heart at 5 to 10 peri-infarct sites. Two-dimensional (2D) transthoracic echocardiography, EF measurements, Holter, and exercise tolerance time (ETT) were performed at baseline, one week (wk), and 6, 12, and 24 months (mo). 96±29 million ABMMNCs were injected into 8.5±2.6 peri-infarct sites over 42±17 minutes (n=20). There were no adverse events associated with the catheter-based cell transplantation procedure or significant increases in ventricular events on Holter. EF improved over baseline from 34.9±4.3% to 41.9±5.1% at 12 mo to 42.2±7.1% (p=0.00005) at 24 mo. ETT improvements were statistically significant from 246±113 sec to 373±183 sec at 12 mo and 371±181 sec at 24 mo (p=0.006). CONCLUSIONS: ABMMNCs delivered with the helical needle transendocardial catheter was safe in this uncontrolled open label study. Increased EF and ETT support the safety of the procedure and technologies involved and warrant additional investigation.

Mechanical properties of completely autologous human tissue engineered blood vessels compared to human saphenous vein and mammary artery.

We have previously reported the initial clinical feasibility with our small diameter tissue engineered blood vessel (TEBV). Here we present in vitro results of the mechanical properties of the TEBVs of the first 25 patients enrolled in an arterio-venous (A-V) shunt safety trial, and compare these properties with those of risk-matched human vein and artery. TEBV average burst pressures (3490+/-892 mmHg, n=230) were higher than native saphenous vein (SV) (1599+/-877 mmHg, n=7), and not significantly different from native internal mammary artery (IMA) (3196+/-1264 mmHg, n=16). Suture retention strength for the TEBVs (152+/-50 gmf) was also not significantly different than IMA (138+/-50 gmf). Compliance for the TEBVs prior to implantation (3.4+/-1.6%/100 mmHg) was lower than IMA (11.5+/-3.9%/100 mmHg). By 6 months post-implant, the TEBV compliance (8.8+/-4.2%/100 mmHg, n=5) had increased to values comparable to IMA, and showed no evidence of dilation or aneurysm formation. With clinical time points beyond 21 months as an A-V shunt without intervention, the mechanical tests and subsequent lot release criteria reported here would seem appropriate minimum standards for clinical use of tissue engineered vessels.