Infection calls for thrombosis: Fact or superstition?

Despite all the efforts, pump thrombosis and thromboembolic complications still remain among the most dreadful complications after long-term ventricular assist device implantation. There is growing evidence that infections, especially blood stream infections predispose to a prothrombotic state despite anticoagulation, and frequently leads to thrombosis and/or embolic events as a consequence. In this short comment, the article by Bouzas et al with heterodox, if not unsettling, conclusions is discussed.

Outcomes of Various Treatment Strategies for Patients with Continuous-Flow Ventricular Assist Device Thrombosis: A Retrospective Analysis.

Pump thrombosis is associated with high morbidity and mortality in patients with a continuous-flow left ventricular assist device. Although it has been defined clearly, the diagnosis and treatment of this complication still remain controversial. Between 2010 and 2014, 163 consecutive patients (mean age: 50.7 ± 13 years, 84% males, median duration of support: 277 (2-1077) days) were implanted a continuous-flow left ventricular assist device. Prospectively collected data of all patients who had at least one pump thrombosis event have been analyzed, retrospectively. Twenty-one pump thrombosis events were observed in 15 patients (9.2%, 0.137 events/patient-year). Median duration of support at the time of first pump thrombosis event was 259 (8-585) days. Overall mortality was 40% (6/15), and overall procedural success was 71.4% (15/21) in our entire cohort. The cause of mortality was hemorrhagic stroke in those who had medical treatment (n = 5), and sepsis and right ventricular failure in the other who had pump exchange. Pump exchange was performed in five patients, of which four survived. Glycoprotein IIb/IIIa antagonists are not beneficial in medical treatment of pump thrombosis. Medical treatment methods including unfractionated heparin and thrombolytics may completely resolve the thrombus and save some patients from pump exchange. In patients where medical treatment does not result in complete thrombus resolution within a reasonable period, and a donor heart is not available, pump exchange is the ultimate solution. Further studies are needed for optimal dosing of thrombolytics to decrease the rate of side effects.

Biodegradable annuloplasty ring two years after implantation: first histological demonstration in human mitral annulus.

Although biodegradable annuloplasty rings have been used in clinics for almost a decade for mitral and/or tricuspid annuloplasty, the fate of the ring at the histological level has not been demonstrated in humans to date. The mitral annulus of a 39-year-old patient who underwent heart transplantation almost two years after annuloplasty was subjected to histological evaluation to demonstrate the mitral annular structures and consequences of biodegradable ring annuloplasty. On examination, the ring was shown to have completely degraded, and a fibrous band had formed in the posterior mitral annulus. No signs of residual calcification were observed. Neighboring structures such as circumflex artery and the great cardiac vein were intact. It can be concluded that the biodegradable annuloplasty ring is completely degraded in humans after implantation, leaving a fibrous band behind to support the posterior annulus. The risk of circumflex artery and great cardiac vein injury may not be considerable if the correct implantation technique is used.

Remote monitoring of left ventricular assist device parameters after HeartAssist-5 implantation.

Although several left ventricular assist devices (LVADs) have been used widely, remote monitoring of LVAD parameters has been available only recently. We present our remote monitoring experience with an axial-flow LVAD (HeartAssist-5, MicroMed Cardiovascular, Inc., Houston, TX, USA). Five consecutive patients who were implanted a HeartAssist-5 LVAD because of end-stage heart failure due to ischemic (n=4) or idiopathic (n=1) cardiomyopathy, and discharged from hospital between December 2011 and January 2013 were analyzed. The data (pump speed, pump flow, power consumption) obtained from clinical visits and remote monitoring were studied. During a median follow-up of 253 (range: 80-394) days, fine tuning of LVADs was performed at clinical visits. All patients are doing well and are in New York Heart Association Class-I/II. A total of 39 alarms were received from three patients. One patient was hospitalized for suspected thrombosis and was subjected to physical examinations as well as laboratory and echocardiographic evaluations; however, no evidence of thrombus washout or pump thrombus was found. The patient was treated conservatively. Remaining alarms were due to insufficient water intake and were resolved by increased water consumption at night and summer times, and fine tuning of pump speed. No alarms were received from the remaining two patients. We believe that remote monitoring is a useful technology for early detection and treatment of serious problems occurring out of hospital thereby improving patient care. Future developments may ease troubleshooting, provide more data from the patient and the pump, and eventually increase physician and patient satisfaction. Despite all potential clinical benefits, remote monitoring should be taken as a supplement to rather than a substitute for routine clinical visits for patient follow-up.

Midterm results of valve repair with a biodegradable annuloplasty ring for acute endocarditis.

BACKGROUND: Conventional annuloplasty rings consist of woven, nondegradable prosthetic material. Their use should theoretically be limited in acute infective endocarditis. Novel biodegradable annuloplasty rings, which are implanted into the annulus, carry theoretical advantages, but have never been evaluated for feasibility and mid-term outcome in such patients. METHODS: Between 2004 and 2009, 17 consecutive patients with acute infective endocarditis (age, 34.5+/-21.6 years; range, 11-82 years; 8 men) had mitral (n=13), tricuspid (n=3), and mitral and tricuspid (n=1) annuloplasty to conclude valve repair. Repair was performed by complete excision of the infected tissue, valvar reconstruction, and biodegradable ring annuloplasty. Prospectively collected clinical and echocardiographic data were analyzed retrospectively. RESULTS: Indications for surgery were heart failure (n=9; 52.9%), hemodynamic instability (n=8; 47%), and persistent infection or sepsis despite antibiotics (n=6; 35.3%). Staphylococci (n=7) and Streptococci (n=4) were the most common causes. Three patients died on postoperative days 1, 2, and 34 because of massive gastrointestinal bleeding; heart failure and pneumonia; and sepsis and acute renal failure, respectively. During a median follow-up of survivors at 29.6 months (range, 2.0 to 51.0 months), no mortality, recurrence, or reoperation occurred. At follow-up, transthoracic echocardiography revealed no or trivial regurgitation in 11 and mild in 3 patients. Left ventricular dimensions regressed significantly after mitral repair. CONCLUSIONS: Valve repair using a biodegradable ring showed good structural and functional properties up to 4 years after repair. Implantation of the biodegradable ring is feasible and effective in patients with acute infective endocarditis. Its intraannular implantation, hindering direct blood contact and associated risk of colonization, represents a theoretical advantage in such patients. Larger comparative studies are needed for further conclusions.

Dynamic human cadaver model for testing the feasibility of new endovascular techniques and tools.

Endovascular device specifications and technical improvements are strongly required, especially in particular anatomical locations such as the aortic arch and the thoracoabdominal aorta. We present a new technique for total endovascular repair of the aortic arch and an experimental design of a circulation model in the human cadaver in order to evaluate the feasibility of this technique.

Paclitaxel-eluting biodegradable synthetic vascular prostheses: a step towards reduction of neointima formation?

BACKGROUND: Clinical small-caliber vascular prostheses are unsatisfactory. Reasons for failure are early thrombosis and late intimal hyperplasia. We thus prepared biodegradable small-caliber vascular prostheses using electrospun polycaprolactone (PCL) with slow-releasing paclitaxel (PTX), an antiproliferative drug. METHODS AND RESULTS: PCL solutions containing PTX were used to prepare nonwoven nanofibre-based 2-mm ID prostheses. Mechanical morphological properties and drug loading, distribution, and release were studied in vitro. Infrarenal abdominal aortic replacement was carried out with nondrug-loaded and drug-loaded prostheses in 18 rats and followed for 6 months. Patency, stenosis, tissue reaction, and drug effect on endothelialization, vascular remodeling, and neointima formation were studied in vivo. In vitro prostheses showed controlled morphology mimicking extracellular matrix with mechanical properties similar to those of native vessels. PTX-loaded grafts with suitable mechanical properties and controlled drug-release were obtained by factorial design. In vivo, both groups showed 100% patency, no stenosis, and no aneurysmal dilatation. Endothelial coverage and cell ingrowth were significantly reduced at 3 weeks and delayed at 12 and 24 weeks in PTX grafts, but as envisioned, neointima formation was significantly reduced in these grafts at 12 weeks and delayed at 6 months. CONCLUSIONS: Biodegradable, electrospun, nanofibre, polycaprolactone prostheses are promising because in vitro they maintain their mechanical properties (regardless of PTX loading), and in vivo show good patency, reendothelialize, and remodel with autologous cells. PTX loading delays endothelialization and cellular ingrowth. Conversely, it reduces neointima formation until the end point of our study and thus may be an interesting option for small caliber vascular grafts.

Papillary fibroelastoma of the left atrial wall: a case report.

Cardiac papillary fibroelastoma is a rare, benign cardiac tumor. It often arises from valvular endocardium, and non-valvular endocardial location is rare. Although transthoracic echocardiography is usually sufficient for the diagnosis of most cardiac tumors, small tumors such as papillary fibroelastoma may be missed. Transesophageal echocardiography is superior to transthoracic echocardiography in diagnosing these tumors. Despite their benign histology, and independent of their size, they should be resected surgically because of their high potential for embolization. In this report, we present a case of papillary fibroelastoma located on the left atrial wall, presenting with symptoms of cerebral ischemia. The patient was treated surgically for the prevention of further embolic complications. Pertinent literature is also reviewed for this rare and benign cardiac tumor.

Alcohol pretreatment of small-diameter expanded polytetrafluoroethylene grafts: quantitative analysis of graft healing characteristics in the rat abdominal aorta interposition model.

Long-term patency rates of small-diameter expanded polytetrafluoroethylene (ePTFE) vascular prostheses are unsatisfactory. Treatment of ePTFE grafts by alcohol before implantation was reported to increase hydrophilic properties, yielding better endothelialization and cellular in-growth, thus improving graft healing. The effect of alcohol pretreatment on ePTFE grafts and postoperative healing characteristics of wet ePTFE grafts were evaluated in this study. Ten sterile ePTFE grafts (2 mm ID, 30 micro thru-pore, 12 mm long) were implanted in the infrarenal aorta of male Sprague-Dawley rats (324-380 g). Five grafts were treated with ethanol 70% and soaked with saline solution before implantation (wet); five nontreated grafts served as control. All rats were sacrificed after digital subtraction angiography and sampling of the graft for histological investigation after 3 weeks. Histomorphometric analysis was performed for endothelial coverage, cellular in-growth, and intimal hyperplasia. All grafts were patent at the end of 3 weeks in both groups. Histological evaluation revealed significantly better endothelial coverage and prominent infiltration by fibroblasts and lymphocytes in the wet group. Endothelial coverage (31.03 +/- 10.61% vs. 13.03 +/- 9.46%, P = 0.03) and cellular infiltration of grafts (50.91 +/- 8.55% vs. 39.29 +/- 10.70%, P = 0.11) were higher in the wet group. Area of intimal hyperplasia per graft length was also higher in the wet group (5.32 +/- 4.75 microm(2)/microm vs. 2.69 +/- 3.41 microm(2)/microm, P = 0.36). Wetting of ePTFE grafts with ethanol 70% pretreatment before implantation might have a beneficial effect on long-term patency of small-diameter vascular grafts due to facilitated graft healing.

Degradation and healing characteristics of small-diameter poly(epsilon-caprolactone) vascular grafts in the rat systemic arterial circulation.

BACKGROUND: Long-term patency of conventional synthetic grafts is unsatisfactory below a 6-mm internal diameter. Poly(epsilon-caprolactone) (PCL) is a promising biodegradable polymer with a longer degradation time. We aimed to evaluate in vivo healing and degradation characteristics of small-diameter vascular grafts made of PCL nanofibers compared with expanded polytetrafluoroethylene (ePTFE) grafts. METHODS AND RESULTS: We prepared 2-mm-internal diameter grafts by electrospinning using PCL (M(n)=80, 000 g/mol). Either PCL (n=15) or ePTFE (n=15) grafts were implanted into 30 rats. Rats were followed up for 24 weeks. At the conclusion of the follow-up period, patency and structural integrity were evaluated by digital subtraction angiography. The abdominal aorta, including the graft, was harvested and investigated under light microscopy. Endothelial coverage, neointima formation, and transmural cellular ingrowth were measured by computed histomorphometry. All animals survived until the end of follow-up, and all grafts were patent in both groups. Digital subtraction angiography revealed no stenosis in the PCL group but stenotic lesions in 1 graft at 18 weeks (40%) and in another graft at 24 weeks (50%) in the ePTFE group. None of the grafts showed aneurysmal dilatation. Endothelial coverage was significantly better in the PCL group. Neointimal formation was comparable between the 2 groups. Macrophage and fibroblast ingrowth with extracellular matrix formation and neoangiogenesis were better in the PCL group. After 12 weeks, foci of chondroid metaplasia located in the neointima of PCL grafts were observed in all samples. CONCLUSIONS: Small-diameter PCL grafts represent a promising alternative for the future because of their better healing characteristics compared with ePTFE grafts. Faster endothelialization and extracellular matrix formation, accompanied by degradation of graft fibers, seem to be the major advantages. Further evaluation of degradation and graft healing characteristics may potentially lead to the clinical use of such grafts for revascularization procedures.

Submitral left ventricular aneurysm: a rare but challenging pathology to treat.

Submitral left ventricular aneurysm is a rare cardiac pathology. Etiology remains still mysterious, but it is believed to be due to a congenital defect of the fibrous layer of the atrioventricular junction. Surgical closure of aneurysm rim is the therapy of choice, despite the diversity of surgical approaches and techniques. We present a young patient operated with a transmitral approach in our clinic. Posterior mitral leaflet (PML) detachment and then extension valvuloplasty by using autologous pericardium was performed in order to save the native mitral valve. We believe that respecting the integrity of native valve is of crucial importance in this young population of patients.

Does harvesting of an internal thoracic artery with an ultrasonic scalpel have an effect on sternal perfusion?

OBJECTIVES: Despite many animal and clinical studies to date, there is still debate on the effect of internal thoracic artery harvesting on postoperative sternal perfusion and thus healing. We performed a prospective clinical study to assess the postoperative sternal perfusion in patients who underwent surgical coronary revascularization by means of unilateral internal thoracic artery harvesting and to evaluate the effect of 2 harvesting methods, namely electrocautery and use of an ultrasonic scalpel. METHODS: Between November 2004 and March 2005, 30 consecutive patients (25 male patients; age, 58.34 +/- 9.42 years; mean New York Heart Association class, 1.90 +/- 0.76) scheduled for conventional coronary surgery were enrolled in this study. After obtaining informed consent, they were randomized into 2 groups. The left internal thoracic artery was harvested as a pedicle graft in all patients by using the corresponding method. All patients underwent 99mTc-methylene diphosphonate bone scintigraphy preoperatively to evaluate baseline sternal perfusion. Control scintigraphy was performed on postoperative day 7. RESULTS: Sternal perfusion showed a significant increase on postoperative scans compared with that at baseline (1067 +/- 191 counts/pixel vs 919 +/- 102 counts/pixel for the right half, P < .001; 1064 +/- 179 counts/pixel vs 905 +/- 107 counts/pixel for the left half, P < .001). There was no significant difference between the right and left sternal halves postoperatively. The method used for harvest had no significant effect on postoperative sternal perfusion (electrocautery = 1037 +/- 121 counts/pixel vs scalpel = 1097 +/- 109 counts/pixel for the right half, P > .05; electrocautery = 1040 +/- 126 counts/pixel vs scalpel = 1089 +/- 130 counts/pixel for the left half, P > .05). CONCLUSIONS: Sternal perfusion increases soon after coronary bypass surgery, probably as a consequence of the healing process, but the source of perfusion for harvest side remains unclear. Harvesting of internal thoracic arteries with an ultrasonic scalpel has no advantageous effects on postoperative sternal perfusion.

Autologous peripheral stem cell transplantation in patients with congestive heart failure due to ischemic heart disease.

OBJECTIVE: Ischemic heart disease accounts for 50% of all cardiovascular deaths and is the leading cause of congestive heart failure. Medical therapy, cardiac assist devices and surgical procedures including heart transplantation have limited efficiency and availability. Stem cell transplantation represents a new therapeutic opportunity for such patients. METHOD: Six patients with the diagnosis of ischemic cardiomyopathy were included in this study. All of the patients had clinical, radiological and echocardiographic signs of heart failure, and reduced left ventricular ejection fraction (LVEF< or =25%). They underwent coronary angiography and stress tests with dobutamine echocardiography, thallium scintigraphy and positron emission tomography to assess myocardial ischemia and viability. Peripheral stem cells were mobilized and collected by apheresis. They were transplanted into areas of injury with open-heart surgery. To increase blood flow to the engrafted areas, coronary artery by-pass surgery was also performed. RESULTS: The patients were followed at least for 4 months. Echocardiography, thallium scintigraphy and positron emission tomography were repeated after at least 6 weeks following surgery. There was a significant increase in life quality and NYHA class. Some benefit was documented on echocardiography, thallium scintigraphy, and positron emission tomography. CONCLUSION: This approach opens a new window in the treatment of 'no hope' patients with congestive heart failure.