Felix Fleissner

Aortic valve replacement in geriatric patients with small aortic roots: are sutureless valves the future?

OBJECTIVES Aortic valve replacement (AVR) in geriatric patients (>75 years) with small aortic roots is a challenge. Patient-prosthesis mismatch and the long cross-clamp time necessary for stentless valves or root enlargement are matters of concern. We compared the results of AVR with sutureless valves (Sorin Perceval), against those with conventional biological valves. METHODS Between April 2007 and December 2012, 120 isolated AVRs were performed in patients with a small annulus (<22 mm) at our centre. In 70 patients (68 females, age 77.4 ± 5.5 years), conventional valves (C group) and in 50 patients (47 females, age 79.8 ± 4.5 years), sutureless valves (P group) were implanted. The Logistic EuroSCORE of the C group was 16.7 ± 10.4 and that of the P group 20.4 ± 10.7, (P = 0.054). Minimal-access surgery was performed in 4.3% (3/70) patients in the C group and 72% (36/50) patients in the P group. RESULTS The cardiopulmonary bypass (CPB) and cross-clamp times of the C group were 75.3 ± 23 and 50.3 ± 14.2 min vs 58.7 ± 20.9 and 30.1 ± 9 min in the P group, (P < 0.001). In the C group, two annulus enlargements were performed. Thirty-day mortality was 4.3% (n = 3) in the C group and 0 in the P group, (n.s.). At follow-up (up to 5 years), mortalities were 17.4% (n = 12) in the C group and 14% (n = 7) in the P group, (n.s.). CONCLUSIONS This study highlights the advantages of sutureless valves for geriatric patients with small aortic roots reflected by shorter cross-clamp and CPB times, even though most of these patients were operated on via a minimally invasive access. Moreover, due to the absence of a sewing ring, these valves are also almost stentless, with greater effective orifice area (EOA) for any given size. This may potentially result in better haemodynamics even without the root enlargement. This is of advantage, as several studies have shown that aortic root enlargement can significantly increase the risks of AVR. Moreover, as seen in this series, these valves may also enable a broader application of minimally invasive AVR.

Microvesicles as Novel Biomarkers and Therapeutic Targets in Transplantation Medicine

Microvesicles (MVs) including exosomes are emerging new biomarkers and potential regulators of inflammation and immunological processes. Such particles contain proteins and genetic information including DNA and microRNAs that may be of importance for cell/cell communication. However, their role during and after organ transplantation and immunomodulatory effects is only in its beginning of understanding. We here, in brief, introduce generation and biological importance of MVs, describe their (patho)physiological roles and their potential use as future biomarkers and therapeutic agents in transplantation medicine. Circulating MVs may have a great potential to detect possible immune rejections and MV modulation may emerge as a therapeutic approach in organ rejection therapy.

Total aortic arch replacement with the elephant trunk technique: single-centre 30-year results

OBJECTIVES The combined disease of the aortic arch and the descending aorta (aneurysms and dissection) remains a surgical challenge. Various approaches have been used to treat this complex pathology. In the two-stage operation, at the first-stage operation, the aortic arch is replaced through a median sternotomy. Later, at the second-stage operation, the descending thoracic aorta is replaced through a lateral thoracotomy. The elephant trunk (ET) technique was introduced by H.G. Borst at our centre in March 1982, greatly simplifying the second-phase operation. We present our 30-year experience. METHODS From March 1982 to March 2012, 179 patients (112 males, age 56.4±12.6 years) received an ET procedure for the combined disease of the aortic arch and the descending aorta (91 aneurysms, 88 dissections (47 acute)). Fifty-six of these patients had undergone previous cardiac operations. Concomitant procedures were performed if necessary. The cerebral protection was done either by deep (till 1999) or moderate hypothermic circulatory arrest and selective antegrade cerebral perfusion (SACP, after 1999). RESULTS Cardiopulmonary bypass (CPB) and X-clamp times were 208.5±76.5 min and 123.7±54.8 min, respectively. The intraoperative mortality and 30-day mortality during the first-stage operation were 1.7% (3/179) and 17.3% (31/179, 15 with AADA), respectively. Perioperative stroke was 7.9% (n=14/176). Postoperative recurrent nerve palsy was present in 18.2% (32/176) and paraplegia in 5.6% (10/176). The second-stage completion operation was performed as early as possible. Fifty-seven second-stage completion procedures were performed, either surgically (n=50) or through interventional techniques (n=7). The intraoperative and 30-day mortality after the second-stage completion procedures were 5.2% (3/57) and 7.0% (4/57), respectively. The stroke, recurrent nerve palsy and paraplegia rates were 0, 0 and 7% (4/54), respectively. CONCLUSIONS The ET technique has greatly facilitated the two-stage approach to the surgical treatment of combined diseases of the aortic arch and descending aorta. The initial learning curve, acute dissections, re-do and concomitant procedures partially explain the higher mortality rate. Despite the development of new hybrid techniques, there is still a role for the classical ET in selected patients, particularly in the context of proven long-term results and cost effectiveness.

Reduction of Driveline Infections Through Doubled Driveline Tunneling of Left Ventricular Assist Devices

The durability of ventricular assist device (VAD) therapy improved steadily over the past years. However, driveline infections remain a challenge. To test whether an improved surgical implantation technique may lower the incidence of infections, we analyzed all patients receiving a VAD implantation in the years 2008 and 2009 (group 1) and compared them with all patients who received a VAD in 2011 (group 2) after we changed our implantation method. The new technique involves tunneling of the driveline into the fascia of the musculus rectus abdominis, resulting in a longer, intrafascial run to achieve a better resistance against ascending infections. We retrospectively analyzed 40 patients in group 1 and 41 patients in group 2. One year after implantation, the infection rate was markedly reduced (22.5% [n = 9] group 1 vs. 4.9% [n = 2] group 2, P < 0.001) by the new implantation method. There was, however, no significant improvement in overall mortality. The Cox regression model identified the implantation method as an independent risk factor for 1 year after implantation driveline infection (P < 0.05). In conclusion, the new tunneling technique marks a great leap forward in long-term VAD treatment. However, overall mortality remains high and needs further improvement.

Do not leave the heart arrested. Non-cardioplegic continuous myocardial perfusion during complex aortic arch repair improves cardiac outcome

OBJECTIVES Myocardial protection with cardioplegia alone may be inadequate during complex aortic arch surgery, potentially resulting in postoperative myocardial insufficiency. We hypothesized that non-cardioplegic continuous myocardial perfusion (CMP) is feasible and safe to protect the heart while operating on the aortic arch, and improves cardiac outcome. METHODS Between April 2010 and April 2014, 144 patients (60% male, age: 60 ± 13 years) underwent complex aortic arch repair in our institution using prefabricated, branched aortic arch grafts. In 36 patients, the hearts were protected with a combination of cardioplegic cardiac arrest during cardiac procedures and subsequent non-cardioplegic CMP group during aortic arch repair. In 108 patients, myocardial protection was achieved by cardioplegic arrest (CA group) only. RESULTS Preoperative risk factors were comparable in both groups. Acute aortic dissection was the indication for surgery in 42% (CMP) and 44% (CA) of patients; 22% (CMP) and 29% (CA) of patients underwent reoperations. Concomitant cardiac procedures were similar. CMP patients received a frozen elephant trunk more frequently (89 vs 66%, P = 0.0096). Cardiopulmonary bypass time (242 ± 50 vs 264 ± 68 min; P = 0.046), and cardiac ischaemic time (49 ± 32 vs 149 ± 56 min, P < 0.0001) were significantly lower in the CMP group. There were no conversions to CA in the CMP group. Aortic arch repair was not prolonged by CMP. Low cardiac output syndrome occurred less frequently in the CMP group (3 vs 22%, P = 0.0052). Thirty-day mortality was significantly lower in the CMP group (6 vs 21%, P = 0.040). There were no cardiac deaths in the CMP group (0 vs 9%, P = 0.067). Neurological outcome was comparable. Blood loss was higher in the CA group (P < 0.001). CONCLUSIONS Routinely protecting the heart during complex aortic arch repair with non-cardioplegic CMP is a valuable new concept. The CMP technique is feasible and safe, does not prolong aortic arch repair, reduces myocardial damage and improves cardiac outcome. Further evaluation in a larger patient cohort is warranted to establish this novel technique.

Comparison between biological and mechanical aortic valve prostheses in middle-aged patients matched through propensity score analysis: long-term results

OBJECTIVES Choice of prosthesis type in middle-aged patients undergoing aortic valve replacement (AVR) is still debated. The aim of this study is to compare long-term follow-up results in middle-aged patients who underwent isolated AVR with a biological or mechanical prosthesis. METHODS A retrospective analysis of a single-centre database was performed to identify patients aged between 55 and 65 years old who underwent isolated AVR with a biological or mechanical prosthesis from January 1996 to January 2008. Sixty patients with a biological aortic valve prosthesis (Group A) were identified and matched through propensity score analysis to other 60 patients with a mechanical aortic valve prosthesis (Group B). RESULTS There was no difference among groups regarding postoperative complications. Follow-up amounted to 117 ± 51 months. In Group A and B patients, 10- and 15-year survival was 77 ± 6 vs 75 ± 6 and 54 ± 13 vs 53 ± 8%, respectively (P = 0.95); 10- and 15-year freedom from structural valve deterioration, 81 ± 7 vs 100 and 64 ± 12 vs 93 ± 5%, respectively (P = 0.003); 10- and 15-year freedom from redo AVR, 87 ± 6 vs 91 ± 5 and 73 ± 11 vs 91 ± 5%, respectively (P = 0.04); 10- and 15-year freedom from endocarditis, 94 ± 3 vs 98 ± 2 and 83 ± 8 vs 98 ± 2%, respectively (P = 0.05); 10- and 15-year freedom from bleeding events, 98 ± 2 vs 96 ± 5 and 88 ± 6 vs 77 ± 10%, respectively (P = 0.98); and 10- and 15-year freedom from cerebrovascular events, 94 ± 3 vs 97 ± 3 and 83 ± 8 vs 97 ± 3%, respectively (P = 0.03). CONCLUSIONS While survival was not different among groups, patients with a biological prosthesis showed a higher valve-related morbidity at follow-up. Therefore, middle-aged patients should preferably receive a mechanical prosthesis.

Single-centre experience with the frozen elephant trunk technique in 251 patients over 15 years

OBJECTIVES Our goal was to present our 15-year experience (2001-2015) with the frozen elephant trunk (FET) technique. METHODS A total of 251 patients (82 with aortic aneurysms, 96 with acute aortic dissection type A, 4 with acute type B dissections, 52 with chronic aortic dissection type A, 17 with chronic type B dissection and 67 redo cases) underwent FET implantation with either the custom-made Chavan-Haverich (n = 66), the Jotec E-vita (n = 31) or the Vascutek Thoraflex hybrid (n = 154) prosthesis. The cases were assigned to an early period (2001-2011) and a contemporary period (2012-present). RESULTS Mean cardiopulmonary bypass time, aortic cross-clamp time, circulatory arrest time and selective antegrade cerebral perfusion time were 241 ± 72, 125 ± 59, 56 ± 30 and 81 ± 34 min, respectively. Incidence of rethoracotomy for bleeding, stroke, spinal cord injury, prolonged ventilatory support (>96 h) and long-term dialysis were 18, 14, 2, 24 and 2%, respectively. The in-hospital mortality rate was 11% (in acute aortic dissection type A, 12%). Of the 2 patients with graft infections, 1 died and the other had a protracted hospital stay. There were 49 second-stage procedures in the downstream aorta: either open surgical [n = 25 (thoraco-abdominal, n = 15; descending, n = 6; infrarenal, n = 4)] or transfemoral endovascular (n = 23). Elective thoracic endovascular aneurysm repair R implantation was successful in all 23 cases. CONCLUSIONS FET results are comparable with those of the published results of the conventional elephant trunk technique. FET is an ideal landing zone for subsequent transfemoral endovascular completion. Patients with graft infections may have dismal results.

Long-term results of the Mitroflow aortic pericardial bioprosthesis in over 800 patients: limited durability and mechanisms of dysfunction†

OBJECTIVES The Mitroflow aortic pericardial bioprosthesis was widely employed in the past. However, some authors have recently reported early structural valve deterioration (SVD) of the Mitroflow LA/LXA model. Thus, we reviewed our experience with the Mitroflow bioprosthesis and studied the risk factors for SVD and mortality. METHODS Records of patients who underwent aortic valve replacement with a Mitroflow bioprosthesis between November 2005 and January 2015 were retrospectively evaluated with Kaplan-Meier, Cox-regression and multistate analysis. Only patients with a complete clinical follow-up were included in the study. Average follow-up was 45 months and ended on 1 April 2016. RESULTS Between November 2005 and January 2015, among the 916 patients undergoing aortic valve replacement with the Mitroflow prosthesis at our Institution, the 832 (90.8%) patients with follow-up information were included into the study. Fifty-two (6.2%) patients developed SVD (stenosis, n  = 38; regurgitation, n  = 7; mixed, n  = 7). Freedom from SVD was 95.4% and 67.9%, at 5 and 9 years, respectively, without differences after stratification according to the prosthesis model ( P  = 0.87) and prosthesis size ( P  = 0.70). At the multivariable analysis, increasing age was identified as a protective factor against SVD (hazard ratio = 0.94, P  < 0.001). Twenty (38.4%) patients with SVD underwent redo aortic valve replacement. At 5 and 9 years, survival was 64.5% and 43.1%, repectively. According to the multistate analysis, the fraction of patients living with degenerated valves at 9 years was 10.0%; 7.1% died following degeneration. CONCLUSIONS The LA/LXA Mitroflow model showed limited long-term durability. Degenerated prostheses showed more stenosis than regurgitation. Patient age played an important role in the development of SVD.

Stent distortion after sutureless aortic valve implantation: a new complication seen with a novel surgical technique.

In recent years, sutureless aortic valves have grown in popularity. As these valves do not need to be anchored with sutures, shorter cardiac ischaemia and extracorporeal circulation times can potentially be achieved. In addition, the absence of a sewing ring in these valves results in a greater effective orifice area for any given size. Postoperative outcome may be improved using sutureless valves especially when combined with minimally invasive surgical techniques. However, sutureless aortic valves present unique surgical risks. We report 2 cases of delayed distortion of a sutureless aortic valve stent resulting in paravalvular leakage and increased transvalvular gradients. One patient underwent a reoperation with an aortic valve replacement using a standard biological aortic valve, the other patient was treated with balloon dilatation of the aortic valve stent.

Long-term follow-up of total arterial revascularization with left internal thoracic artery and radial artery T-grafts: survival, cardiac morbidity and quality of life

OBJECTIVES Coronary artery bypass grafting is the gold standard for the treatment of patients with multiple-vessel coronary artery disease. The long-term outcome can be improved using arterial grafts. We analysed the initial series of patients who underwent total arterial revascularization at our institute using left internal thoracic artery (LITA) and radial artery (RA) composite T-grafts and had a follow-up of >10 years. METHODS We included all patients who received an isolated, non-emergent total arterial revascularization using LITA-RA T-grafts between September 1996 and August 2001 in our institution. We performed a follow-up of 138 patients (104 male, 60 ± 9 years old). RESULTS Early outcome was excellent. The 30-day mortality, reoperation, neurological complication and myocardial ischaemia rate was 1% (n = 2), 5% (n = 7), 2% (n = 3) and 2% (n = 3), respectively. Mean follow-up was 11 ± 3 years. Long-term survival was 79% (n = 86). There were seven cardiac deaths during follow-up. Freedom from major cardiovascular events for 1, 5 and 10 years was 97, 91 and 84%, respectively. A total of 95 coronary angiographies were performed 4.6 ± 4.1 years postoperatively. In total, 453 anastomoses using the composite graft (LITA-RA as T-graft) were performed. During follow-up, 35 anastomoses were occluded (30 RA anastomoses and 5 LITA anastomoses), leading to an occlusion rate of 7.7% during follow-up. Percutaneous coronary intervention was performed in 18 cases and coronary reoperation in two cases during follow-up. Quality-of-life assessment by Minnesota Living with Heart Failure Questionnaire revealed excellent results. CONCLUSIONS Total arterial revascularization using composite LITA-RA T-grafts leads to excellent long-term results after >10 years.