Carlo Antona

Targeting Landing Zone 0 by Total Arch Rerouting and TEVAR: Midterm Results of a Transcontinental Registry

BACKGROUND Landing zone 0, defined as a proximal landing zone in the ascending aorta, remains the last frontier to be taken. Midterm results of total arch rerouting and thoracic endovascular aortic repair (TEVAR) extending into landing zone 0 remain to be determined. METHODS From 2003 to 2011, 66 patients (mean age, 70 years; 68% men) presenting with pathologic conditions affecting the aortic arch (atherosclerotic aneurysms [n = 48], penetrating ulcers [n = 6], type B dissections [n = 6], type B after type A dissections [n = 5], and anastomotic aneurysm [n = 1]) were treated in 5 participating centers. Of these 66 patients, only 12% would have been deemed suitable for any kind of conventional surgical repair because of multisegmental aortic disease or comorbidities. RESULTS In-hospital mortality was 9%. Retrograde type A dissection was observed in 3% of patients. The assisted type I and type III endoleak rate was 0%. Stroke was seen in 5% of patients. Permanent paraplegia was observed in 3% of those studied. Median follow-up was 25 months (8-41 months). There was 1 late type Ib endoleak, which was followed by watchful waiting. Five-year survival was 72%. Five-year aorta-related survival was 96%. No aorta-related reintervention had to be performed in the segments treated. CONCLUSIONS Midterm results of total arch rerouting and TEVAR extending into landing zone 0 are excellent in regard to aorta-related survival and freedom from aorta-related reintervention. Retrograde type A dissection, potentially related to compliance mismatch between the ascending aorta and the stent-graft, warrants further attention. Extended application of this strategy augments therapeutic options in a group of patients who are not suitable candidates for conventional therapy.

Aortic root performance after valve sparing procedure: a comparative finite element analysis

David and Yacoub sparing techniques are the most common procedures adopted for the surgical correction of aortic root aneurysms. These surgical procedures entail the replacement of the sinuses of Valsalva with a synthetic graft, inside which the cusps are re-suspended. Root replacement by a synthetic graft may result in altered valve behaviour both in terms of coaptation and stress distribution, thus leading to the failure of the correction. A finite element approach was used to investigate this phenomenon; four 3D models of the aortic root were developed to simulate the root in physiological, pathological and post-operative conditions after the two different surgical procedures. The physiological 3D geometrical model was developed on the basis of anatomical data obtained from echocardiographic images; it was then modified to obtain the pathological and post-operative models. The effectiveness of both techniques was assessed by comparison with the first two simulated conditions, in terms of stresses acting on the root, leaflet coaptation and interaction between leaflets and the graft during valve opening. Results show that both sparing techniques are able to restore aortic valve coaptation and to reduce stresses induced by the initial root dilation. Nonetheless, both techniques lead to altered leaflet kinematics, with more evident alterations after David repair.

Assessment of an aortosaphenous vein graft anastomotic device in coronary surgery: Clinical experience and early angiographic results

BACKGROUND Until now technologic evolution in coronary bypass surgery has focused on extracorporeal circulation, on operation without extracorporeal circulation, and on the exposure of the operative site. Recently a one-shot anastomotic device for the proximal anastomosis in coronary surgery was developed. We investigated whether the use of the aortic connector system (ACS) could facilitate the creation of aortosaphenous vein graft anastomoses in myocardial revascularization. METHODS From November 2000, 40 ACS devices were used in 36 consecutive patients (mean age 70.7 +/- 8.9 years); 12 patients (33.3%) underwent surgery on pump and 24 patients (66.6%) off pump; 50 distal anastomoses were performed. In all cases the connection with the ascending aorta was created before the distal anastomoses because of the necessity to slide the saphenous vein graft (SVG) over the vein transfer sheath. Intraoperative graft function was tested measuring blood flow by Doppler analysis. Postoperative evaluation of the anastomotic patency was carried out by early angiography in 34 patients (94.7%) but was excluded in 5 patients (5.3%) with extensive extracardiac vascular occlusive disease. RESULTS Of 38 AC (95%) evaluated, 36 (94.7%) functioned properly. The end-to-side proximal anastomosis without aortic clamping is instantaneous, the quality of anastomoses was highly rated, no additional stitches were required, and all coronary arteries could be reached. Intraoperative quantity flow was measured by Doppler analysis and all but one showed good flow. Early postoperative angiography demonstrated good patency of the grafts in all cases but 2 (5.3%). At 1-year follow-up, 1 patient died of stroke; all other patients remained free of symptoms and no reoperation was required. CONCLUSIONS The use of ACS makes end-to-side anastomosis rapid, effective, and reproducible while eliminating aortic cross clamping; it opens a new era in beating or nonbeating coronary surgery. Long-term results are mandatory to confirm our favorable preliminary results.

Myocardial revascularization with multiple arterial grafts: comparison between the radial artery and the right internal thoracic artery

BACKGROUND Bilateral internal thoracic artery (ITA) harvesting is significantly underused, whereas the radial artery is being used with increasing frequency. We have retrospectively analyzed perioperative and short-term outcomes of patients receiving a radial artery versus those receiving a right ITA as a second arterial graft. METHODS Between February 1999 and May 2000, 250 patients underwent coronary artery bypass grafting using the radial artery (156 patients) or the right ITA (94 patients) in combination with the left ITA and, when required, the saphenous vein. RESULTS There was a higher prevalence of risk factors in the radial artery group. More coronary artery bypass graftings (p < 0.001) were performed with the radial artery. Operative mortality was not different (p = not significant). In the right ITA group there was more bleeding (p < 0.001) and a longer hospital stay (p < 0.001). Mean follow-up was 8.1 +/- 3.9 months. The probability of survival was similar (p = not significant). CONCLUSIONS The radial artery can extend the benefits of multiple arterial grafting to those patients who are usually excluded from bilateral ITA harvesting because of multiple risk factors. Perioperative and short-term results are good.

Hypertonicity Induces Injury to Cultured Human Endothelium: Attenuation by Glutamine

BACKGROUND Although most preservation solutions as well as some cardioplegic solutions used for organ storage and transplantation are hypertonic, the effects of extracellular hypertonicity on endothelium are not well established. Aims of this study were to evaluate the response of cultured human saphenous vein endothelial cells to extracellular hypertonicity and to investigate the role of the amino acid glutamine in preventing endothelial damage in vitro. METHODS Eight distinct strains of human saphenous vein endothelial cells were studied. Hypertonic (350 and 400 mosm/kg) media were obtained by supplementing culture medium with sucrose. Cell viability was assessed in the absence or the presence of glutamine through the determination of cell number and protein content of the cultures. Confocal microscopy of cells loaded with the fluorescent dye calcein was also performed. RESULTS Exposure of human saphenous vein endothelial cells to hypertonic media without glutamine caused significant cell loss within 30 minutes. Cell loss progressed steadily during incubation and after 6 hours reached 50% at 350 mosm/kg and 65% at 400 mosm/kg. In the presence of 2 mmol/L glutamine, endothelial damage was completely prevented at 350 mosm/kg and significantly lessened at 400 mosm/kg compared with glutamine-free media. Confocal microscopy showed that most hypertonicity-treated cells exhibited the typical features of an apoptotic death and confirmed the osmoprotective effect of glutamine. CONCLUSIONS These results indicate that the supplementation of hypertonic storage solutions with glutamine might exert a partial osmoprotective effect and suggest that the relationship between endothelial damage and tonicity of storage and cardioplegic solutions should be carefully investigated.

Minimally invasive direct coronary artery bypass grafting: midterm results and quality of life

BACKGROUND There is increasing interest in minimally invasive direct coronary artery bypass grafting (MID-CABG); however, there is still little information about midterm results and postoperative quality of life. METHODS From March 1995 to March 1998, 64 patients underwent MIDCABG at our hospital. Their mean age was 60+/-9.5 years; 22 (34.4%) had unstable angina. All patients were followed-up by both direct visit and questionnaire to assess the postoperative quality of life. RESULTS There were no perioperative deaths nor conversions to sternotomy; the perioperative myocardial infarction rate was 1/64 (1.6%). Predischarge angiography showed overall and unobstructed patency rates of 96.8% (62 of 64) and 93.8% (60 of 64), respectively. At follow-up (25+/-11.4 months) actuarial survival was 100%, and survival free of myocardial infarction was 98.4%+/-1.6% at 3 years. Both the Physical Activity Score and the Psychological General Well-being Index improved significantly after the operation, with percentage improvements of 31% and 23%, respectively, at 12 months postoperatively. CONCLUSIONS In selected patients MIDCABG can be a reliable and safe option. Patients who undergo this procedure are free of major complications and enjoy a good quality of life after surgery.

In vitro hemodynamics and valve imaging in passive beating hearts.

Due to their high complexity, surgical approaches to valve repair may benefit from the use of in vitro simulators both for training and for the investigation of those measures which can lead to better clinical results. In vitro tests are intrinsically more effective when all the anatomical substructures of the valvular complexes are preserved. In this work, a mock apparatus able to house an entire explanted porcine heart and subject it to pulsatile fluid-dynamic conditions was developed, in order to enable the hemodynamic analysis of simulated surgical procedures and the imaging of the valvular structures. The mock loops hydrodynamic design was based on an ad-hoc defined lumped-parameter model. The left ventricle of an entire swine heart was dynamically pressurized by an external computer-controlled pulse duplicator. The ascending aorta was connected to a hydraulic circuit which simulated the input impedance of the systemic circulation; a reservoir passively filled the left atrium. Accesses for endoscopic imaging were located in the apex of the left ventricle and in the aortic root. The experimental pressure and flow tracings were comparable with the typical in vivo curves; a mean flow of 3.5±0.1l pm and a mean arterial pressure of 101±2 mmHg was obtained. High-quality echographic and endoscopic video recordings demonstrated the systems excellent potential in the observation of the cardiac structures dynamics. The proposed mock loop represents a suitable in vitro system for the testing of minimally-invasive cardiovascular devices and surgical procedures for heart valve repair.

Type 2 Diabetes Mellitus Is Associated With Faster Degeneration of Bioprosthetic Valve Results From a Propensity Score–Matched Italian Multicenter Study

BACKGROUND The present study was aimed at determining the impact of type 2 diabetes mellitus (DM) on postoperative bioprosthetic structural valve degeneration. METHODS AND RESULTS Twelve Italian centers participated in the study. Patient data refer to bioprosthetic implantations performed from November 1988 to December 2009, which resulted in 6184 patients (mean age 71.3±5.4 years, 60.1% male) being enrolled. Of these patients, 1731 (27.9%) had type 2 DM. The propensity score-matching algorithm successfully matched 1113 patients with type 2 DM with the same number of no-DM patients. The postmatching standard differences were less than 0.1 for each of the covariates, and 64.2% of DM patients were matched. The early (30 days) mortality rate was 7.8% (n=87) versus 2.9% (n=33) in patients with or without type 2 DM (P<0.001), respectively. Seven-year freedom from valve deterioration was significantly lower in patients with DM (73.2% [95% confidence interval, 61.6-85.5] versus 95.4% [95% confidence interval, 83.9-100], P<0.001). In Cox regression models with robust SEs that accounted for the clustering of matched pairs, DM was the strongest predictor of structural valve degeneration (hazard ratio 2.39 [95% confidence interval 2.28-3.52]). When we allowed for interaction between type 2 DM and other key risk factors, DM remained a significant predictor beyond any potentially associated variable. CONCLUSIONS Patients with type 2 DM undergoing bioprosthetic valve implantation are at high risk of early and long-term mortality, as well as of structural valve degeneration.Background— The present study was aimed at determining the impact of type 2 diabetes mellitus (DM) on postoperative bioprosthetic structural valve degeneration. Methods and Results— Twelve Italian centers participated in the study. Patient data refer to bioprosthetic implantations performed from November 1988 to December 2009, which resulted in 6184 patients (mean age 71.3±5.4 years, 60.1% male) being enrolled. Of these patients, 1731 (27.9%) had type 2 DM. The propensity score–matching algorithm successfully matched 1113 patients with type 2 DM with the same number of no-DM patients. The postmatching standard differences were less than 0.1 for each of the covariates, and 64.2% of DM patients were matched. The early (30 days) mortality rate was 7.8% (n=87) versus 2.9% (n=33) in patients with or without type 2 DM ( P <0.001), respectively. Seven-year freedom from valve deterioration was significantly lower in patients with DM (73.2% [95% confidence interval, 61.6–85.5] versus 95.4% [95% confidence interval, 83.9–100], P <0.001). In Cox regression models with robust SEs that accounted for the clustering of matched pairs, DM was the strongest predictor of structural valve degeneration (hazard ratio 2.39 [95% confidence interval 2.28–3.52]). When we allowed for interaction between type 2 DM and other key risk factors, DM remained a significant predictor beyond any potentially associated variable. Conclusions— Patients with type 2 DM undergoing bioprosthetic valve implantation are at high risk of early and long-term mortality, as well as of structural valve degeneration. # Clinical Perspective {#article-title-46}

Predictors and outcomes of acute kidney injury after thoracic aortic endograft repair

BACKGROUND This study analyzed the incidence and the predictive factors of postoperative acute kidney injury (AKI) after thoracic endovascular aortic repair (TEVAR) and evaluated the effect of AKI on postoperative survival. METHODS Between November 2000 and April 2011, all consecutive patients undergoing TEVAR of the descending thoracic or thoracoabdominal aorta were enrolled at four teaching hospitals. Estimated glomerular filtration rate (eGFR) was evaluated during the entire hospitalization. AKI was defined by the RIFLE (Risk, Injury, Failure, Loss of function, End-stage renal disease) consensus criteria. RESULTS The study included 171 patients (80% men) who were a mean age of 69±14 years (range, 18-87 years). AKI occurred in 24 patients (14%). Independent predictors of postoperative AKI were preoperative depressed eGFR, thoracoabdominal extent, and postoperative transfusion. Patients with AKI experienced major postoperative complications (P=.001), longer hospitalization (P=.008), and higher hospital mortality (29% vs 4%; P<.001). Kaplan-Meier analysis showed a survival of 82%, 51%, and 51% at 1, 3, and 5 years for patients who developed AKI, which was significantly worse than the 99%, 89%, and 80% for patients who did not experience AKI (P=.001). CONCLUSIONS Preoperative poor renal function, blood transfusions, and the thoracoabdominal extent of the aortic disease were the most important predictors for AKI.

Ectopic Thyroid Tissue in the Ventricular Outflow Tract: Embryologic Implications

The case of a 66-year-old female patient with a tumor located in the right ventricular outflow tract is reported. Histologic examination of an intraoperative biopsy revealed that the tumor was an intracardiac ectopic thyroid. We performed conservative surgery with partial resection of the mass. After 5 years, the patient is asymptomatic and leading a normal life. The authors examine the relation between the embryologic development of the primitive heart and the thyroid primordium and suggest the hypothesis of ectopic thyroid location in the right- or left-ventricular outflow tract.