Investigation of failure modes of explanted porcine valves in the mitral position

BackgroundPorcine valves are used for mitral valve replacement, but the limited long-term durability has restricted the application in younger patients. Degenerated porcine mitral valves were explanted to analyze the failure modes and damage characteristics.MethodsTwelve porcine valves were explanted via secondary mitral valve replacement surgery. Microcomputed tomography scanning, morphological and pathological examinations were performed to classify the cusp tears, calcification, and pannus formation. The causes of valve deterioration were subsequently analyzed.ResultsThe mean age at first implantation was 45.42±19.58 years (range, 11–64 years). The mean duration of implantation was 9.39±4.14 years (range, 4.25–18.75 years). The indications for first surgery were rheumatic heart disease in 8 patients (66.67%), infective endocarditis in 2 patients (16.67%), degenerative valvular disease in one patient (8.33%), and congenital heart disease in one patient (8.33%). Type I cusp tears and commissural dehiscence that occurred near the stent post position were found in 6 (50%) and 5 (41.67%) valves, respectively. Calcification was detected in 6 (50%) cases, and pannus was found in most valves (91.67%).ConclusionsLeaflet damage occurred near the stent posts area was the main failure mode of porcine mitral valves in this study. Patients who undergo the first surgery at younger age, the higher prevalence rate of rheumatic heart disease, the structure of bioprosthetic porcine valve, and left ventricular stresses could be considered as the main factors causing valve deterioration.     

Formation of pannus on prosthetic valves in a child with pseudoxanthoma elasticum

A child with pseudoxanthoma elasticum had mitral valvar prolapse with severe regurgitation necessitating replacement with a prosthetic valve. Extensive formation of pannus caused obstruction of two mechanical valves, one after twenty months and the second after three years. Histology of the pannus was similar to the endocardial lesions that are considered unique to pseudoxanthoma elasticum.     

Mechanical valve obstruction: Review of diagnostic and treatment strategies

Prosthetic valve obstruction (PVO) is a rare but feared complication of mechanical valve replacement. Diagnostic evaluation should focus on differentiating prosthetic valve thrombosis (PVT) from pannus formation, as their treatment options differ. History of sub-optimal anti-coagulation and post-op time course to development of PVO are useful clinical characteristics in differentiating thrombus from pannus formation. Treatment of PVT is influenced by the patient’s symptoms, valve location, degree of obstruction and thrombus size and may include thrombolysis or surgical intervention. Alternatively, pannus formation requires surgical intervention. The purpose of this article is to review the pathophysiology, epidemiology, diagnostic approach and treatment options for aortic and mitral valve PVO.     

Live 3D TEE demonstrates and guides the management of prosthetic mitral valve obstruction

A 43-year-old woman, with a remote history of rheumatic mitral stenosis and a St. Jude prosthetic mitral valve replacement, presented with shortness of breath and palpitations, shortly after a long flight. On admission, atrial fibrillation with a rapid ventricular response was noted in the setting of a long history of noncompliance with her anticoagulation. Transesophageal echocardiography (TEE) demonstrated multiple laminated thrombi in the left atrial appendage. Live three-dimensional (3D) TEE confirmed this diagnosis and demonstrated an immobile posterior leaflet of the mitral prosthesis, which had direct implications in her management. She successfully underwent surgery for mitral valve replacement, left atrial appendage ligation, and a Maze procedure on the following day. The multiple thrombi within the atrial appendage were confirmed intraoperatively and pannus formation was determined to be the etiology of the leaflet immobility.     

Effect of fibroblast growth factor-2 on pannus formation in replacement prosthetic heart valves

BACKGROUND AND AIM OF THE STUDY: Fibroblast growth factor-2 (FGF-2) is a multifunctional protein which plays a role in smooth muscle cell growth, wound healing, tissue repair and angiogenesis. FGF-2 is also released by mechanically wounded cells. Herein, the importance of FGF-2 release from periannular tissue in the mechanism of pannus formation in obstructed mechanical prostheses was investigated. METHODS: Between January 1993 and December 2002, 35 patients with an obstructed bileaflet prosthetic mitral valve were classified according to the nature of obstruction as either thrombus or pannus. Data were related to patient age and gender, prosthesis model and size, intraoperative and pathology findings, and interval between implant and thrombosis. FGF-2 release was monitored immunohistochemically in all cases. RESULTS: Thrombus formation was found in 19 patients, and pannus formation in 16. Patients were reoperated on after 3.10 +/- 0.7 years in the thrombus group, and after 6.3 +/- 0.46 years in the pannus group (p = 0.04). A foreign body reaction was found 78.9% of thrombus patients and 81.2% of pannus patients (p = 0.602), chronic inflammation in 31.5% and 50%, respectively (p = 0.317), and FGF-2 release in 78.9% and 87.5%, respectively (p = 0.582). CONCLUSION: As FGF-2 release was similar in both patient groups, the duration of FGF-2 release from injured periannnular tissue was considered to form part of the chronic healing process, and was not attributed to mitral valve obstruction by pannus formation.     

Risk factors for impaired neurological outcome after thoracic aortic surgery

BackgroundWe aimed to identify risk factors for an impaired postoperative neurological outcome after thoracic aortic surgery.MethodsData from all patients undergoing thoracic aortic surgery between 2010 and 2020 at our institution were collected and analyzed retrospectively. Logistic regression analysis was used to identify independent risk factors for permanent postoperative neurological deficit (ND) (stroke), which was defined as a ND lasting at least seven days.ResultsThoracic aortic surgery was performed in 1,334 patients. Of these, 286 (21.4%) underwent emergency surgery. The mean EuroSCORE II was 8.6±10.1. A perioperative stroke occurred in 94 patients (7.0%). Of all strokes, 62.8% (n=59) were considered of embolic and 24.5% (n=23) of hemodynamic origin. In elective procedures, stroke rates ranged from 0.5% after valve-sparing root replacement to 8.1% after arch surgery. Adjusted logistic regression identified advanced age [>70 years; odds ratio (OR), 1.83; P=0.009], acute type A dissection (ATAD) (OR, 1.69; P=0.0495), aortic arch surgery (OR, 3.24; P<0.001), concomitant coronary artery bypass grafting (CABG) (OR, 2.19; P=0.005), and high extracorporeal circulation (ECC) time (>230 min; OR, 1.70; P=0.034) as independent risk factors for all strokes. Secondary endpoint analyses revealed that risk factors for hemodynamic stroke were arch surgery, advanced age (>70 years), atherosclerosis, and ATAD. Risk factors for embolic stroke were arch surgery, concomitant CABG and preoperative cerebral malperfusion.ConclusionsIdentified independent risk factors for all strokes were advanced age, ATAD, arch surgery, concomitant CABG, and high ECC time. Hemodynamic and embolic strokes show distinct risk profiles.     

Intermittent acute aortic valve regurgitation: a case report of a prosthetic valve dysfunction.

Complications of any mechanical prosthesis include thrombus or pannus formation. In our case report we demonstrate that prosthetic aortic valve regurgitation due to pannus formation may be intermittent and non-cyclic in pattern and therefore not obvious at the time of original clinical examination. Under these conditions and as transesophageal echocardiography cannot be repeated promptly, transthoracic 2-D and Doppler echocardiography should be available at any time when symptoms occur and present the method of choice for acute patient evaluation. Thrombolysis seems to be the first treatment of choice in case of thrombus formation and re-do surgery in case of pannus formation.     

Quattro valve trial at mid-term: December 1996 to November 2004

BACKGROUND AND AIM OF THE STUDY: The Quattro valve is a stentless pericardial mitral bioprosthesis that is treated with a post-tanning aldehyde capping designed to reduce calcification. A prospective trial was started in December 1996; herein are reported the results of the three centers that performed the surgery and followed up patients in the majority of cases. Young patients were deliberately included in the trial. METHODS: Follow up data from 175 patients (mean age 46 years; range: 12-87 years) were collected and analyzed. Among patients, 44% were aged < 40 years. Follow up was 91% complete; mean follow up was 3.4 years (range: 0-7.5 years); total follow up was 465 patient-years (pt-yr). Clinical outcome was assessed according to the AATS/STS guidelines, and results analyzed according to Kaplan-Meier product limit calculation and by FDA Optimal Performance Criteria (OPC). RESULTS: Early mortality was 1.7% (all non-valve related). At 60 months after surgery, mean overall survival was 84.8 +/- 3.6%, mean overall freedom from valve-related death was 99.2 +/- 0.9%, and mean overall freedom from calcification, pannus and tears was 96.1 +/- 2.2%. FDA OPC values (data for mechanical valve, tissue valve, Quattro valve in patients aged < 40 years and of all ages, respectively; expressed as %/pt-yr) were as follows: thromboembolism/stroke 3.0, 2.5, 0, 0.4; thrombosis 0.8, 0.2, 0, 0; major hemorrhage 1.5, 0.9, 0, 0.4; major perivalvular leak 0.6, 0.6, 0.4, 0.6; late endocarditis 1.2, 1.2, 1.8, 1.3; calcification/pannus 0, 0, 0.8, 0.6. Statistical analysis of these data showed there to be no difference between patients aged less or more than 40 years. CONCLUSION: Overall mid-term results with the Quattro valve were acceptable. The lack of early calcification in young patients shows promise. More young patient-years of follow up will be needed to establish a secure indication for use in young, rheumatic patients where anticoagulation control is deficient.     

Use of intra-cardiac ultrasound in the diagnosis of prosthetic valve malfunction.

A 46-year old lady was under regular follow up for aortic valve replacement done in 2002 for aortic stenosis. The valve was a Carbomedics 19 mm bi-leaflet aortic valve prosthesis for which she had adequate anticoagulation since implantation. She had a past history of end stage renal failure, type 2 diabetes, hypertension, cerebrovascular disease and systemic lupus erythematosus. She was asymptomatic and had a routine transthoracic echocardiogram performed which revealed that her aortic valve prosthesis was well seated with an elevated velocity across the valve; the aortic valve leaflets were poorly visualised but appeared to be mobile. A transoesophageal echocardiogram (TOE) confirmed the markedly increased forward velocity across the aortic valve (maximum velocity 4.6 m/s) with small aortic root raising the possibility of pressure recovery phenomenon. Once again the leaflets were not clearly seen but appeared mobile despite the use of deep trans-gastric view. Fluoroscopy was performed and revealed that one of the leaflets was not moving. The patient had an intra-cardiac ultrasound scan (ACUSON AcuNav; Siemens) with the probe of the scanner within the right atrium. A long-axis view demonstrated the prosthetic aortic valve leaflets clearly (Fig. 1). A short-axis view of the prosthetic valve revealed an echogenic area at the six o'clock position; this may be due to pannus formation (Fig. 2); colour flow across the valve during systole revealed absence of colour flow though one of the leaflets due to the leaflet being stuck (Fig. 3). The sewing cuff of the Carbomedics valve is coated with biolite carbon, which is an anti-thrombotic agent that prevents adhesion of thrombus or pannus on the sewing cuff. There are few reports of Carbomedics valve dysfunction by pannus formation in the mitral position but none in the aortic position. Fluoroscopy can be used to visualize mobility of valve leaflets but is unable to identify thrombus/pannus formation that may be causing the valve to stick. Intra-cardiac echocardiography (ICE) can provide additional information regarding potential causes of valve dysfunction such as pannus/thrombus formation. However, ICE does suffer from the same limitations as TOE in obtaining sufficiently adequate images of the aortic valve to allow appropriate assessment of leaflet motion and insight into flow channels; it is also more invasive and expensive compared with other imaging modalities. In our patient ICE provided better images than TOE, possibly due to the closer proximity of the probe to the aortic root compared with TOE. ICE is a novel tool in the assessment of prosthetic valve function, which can complement data obtained from transthoracic/transoesophageal echocardiography and fluoroscopy.     

Thrombosis of mitral valve prosthesis presenting as abdominal pain.

A 67-year-old woman presented with abdominal pain, anemia, and leukocytosis. Five years previously, the patient had undergone mitral valve replacement with a St. Jude bileaflet mechanical prosthesis. After her admission, echocardiography confirmed an immobile leaflet of the prosthetic valve. At urgent surgery, thrombosis and pannus, obstructing the disc, were found, and the mechanical valve was replaced with a bioprosthesis. The incidence of mitral valve thrombosis is low, ranging from 0.1% to 5.7% per patient per year. Patients who receive inadequate anticoagulation, particularly with valve prostheses in the mitral position, have an increased risk for thrombus or pannus formation. Presentation varies, from symptoms of congestive heart failure or systemic embolization, to fever or no symptoms. New or worsening symptoms in a patient with a prosthetic heart valve should raise concerns about prosthetic dysfunction. Aggressive investigation and, if indicated, urgent or emergency surgery for treatment can be lifesaving.     

A Population-Based Study of 30-day Incidence of Ischemic Stroke Following Surgical Neck Dissection

The objective of this study was to determine the 30-day incidence of ischemic stroke following neck dissection compared to matched patients undergoing non-head and neck surgeries.A surgical dissection of the neck is a common procedure performed for many types of cancer. Whether such dissections increase the risk of ischemic stroke is uncertain.A retrospective cohort study using data from linked administrative and registry databases (1995–2012) in the province of Ontario, Canada was performed. Patients were matched 1-to-1 on age, sex, date of surgery, and comorbidities to patients undergoing non-head and neck surgeries. The primary outcome was ischemic stroke assessed in hospitalized patients using validated database codes.A total of 14,837 patients underwent surgical neck dissection. The 30-day incidence of ischemic stroke following the dissection was 0.7%. This incidence decreased in recent years (1.1% in 1995 to 2000; 0.8% in 2001 to 2006; 0.3% in 2007 to 2012; P for trend <0.0001). The 30-day incidence of ischemic stroke in patients undergoing neck dissection is similar to matched patients undergoing thoracic surgery (0.5%, P = 0.26) and colectomy (0.5%, P = 0.1). Factors independently associated with a higher risk of stroke in 30 days following neck dissection surgery were of age ≥75 years (odds ratio (OR) 1.63, 95% confidence interval (CI) 1.05–2.53), and a history of diabetes (OR 1.60, 95% CI 1.02–2.49), hypertension (OR 2.64, 95% CI 1.64–4.25), or prior stroke (OR 4.06, 95% CI 2.29–7.18).Less than 1% of patients undergoing surgical neck dissection will experience an ischemic stroke in the following 30 days. This incidence of stroke is similar to thoracic surgery and colectomy.     

A retrospective analysis of factors influencing re-operation in patients undergoing mechanical valve replacement

Background

We aimed to determine the possible factors leading to re-operation in patients undergoing mechanical valve replacement and to investigate the relationship between valvular thrombus formation and mean platelet volume.

Methods

The medical records of 43 patients with mechanical valve implantation, who were admitted to the Department of Cardiovascular Surgery of Dr Siyami Ersek Thoracic and Cardiovascular Surgery Training and Research Hospital between 2000 and 2005 were analysed retrospectively. Data recorded included demographic characteristics, valve type, size and location, implantation position, warfarin use, INR level, additional cardiac intervention, presence of left atrial thrombus, valvular thrombus, pannus formation, perivalvular leak, left atrial aneurysm, platelet count and mean platelet volume (MPV), bleeding after the primary surgery and/or revision of surgery due to other reasons, valve protection, aortic root expansion, presence of valve calcification and infective endocarditis, pre- and postoperative rhythm pattern, brand name of prosthesis, distance of the patient’s house from a cardiac surgery centre, and concomitant non-cardiac systemic diseases.

Results

Mean age was 49.3 years (range 19–78 years). Of the patients, 51% (n = 22) were males and 49% (n = 21) were females. The re-operation mortality was 11.6%. Age, gender, valve type, brand of valve prosthesis, and implantation position were not risk factors for re-operation. The MPV was higher and statistically significant in patients with valvular thrombus during re-operation (p < 0.001). MPV was determined to be an independent risk factor with 85% sensitivity and 87% specificity.

Conclusion

MPV and INR levels should be closely monitored when designing individualised postoperative medical treatment for patients undergoing heart valve re-operation.     

How far should we treat metastatic liver cancer? Report of three long-term survivors

The major issue in treating metastatic liver cancer is: how far should we perform resection? We believe that only reports of long-term survival afford an answer to this problem. We report three such patients. The first patient underwent pancreatoduodenectomy for cancer of the papilla of the duodenum and resection of metastatic liver cancer. She is alive without recurrence 15 years and 1 month after the initial surgery. The second patient received low anterior resection for rectal cancer, extended right lobectomy for liver metastasis, and pancreatoduodenectomy for metastasis at the common bile duct. She survived 6 years and 9 months after the initial surgery. The third patient underwent right nephrectomy for Wilms' tumor (adult type), extended right lobectomy for liver metastasis, and repeat resection of recurrences at the mediastinum and in the thoracic and abdominal walls. She is alive 21 years and 2 months after the initial surgery. These experiences have prompted us to carry out resection when surgery is deemed feasible.     

Mitral valve-sparing procedures and prosthetic heart valve failure: A case report

Prosthetic heart valve dysfunction due to thrombus or pannus formation can be a life-threatening complication. The present report describes a 47-year-old woman who developed valvular cardiomyopathy after chorda-sparing mitral valve replacement, and subsequently underwent heart transplantation for progressive heart failure. The explanted mitral valve prosthesis showed significant thrombus and pannus leading to reduced leaflet mobility and valvular stenosis. The present report illustrates the role of the subvalvular apparatus and pannus in prosthesis dysfunction.     

Occult Cushing's disease presenting with acute psychosis

A 37-year-old woman presented with acute psychosis and cognitive impairment. Skull x-ray showed an enlarged sella turcica with erosion of the floor. Endocrinologic workup suggested the diagnosis of Cushing's disease and hyperprolactinemia. She had no cushingoid feature, and the only physical sign was mild generalized obesity. She showed a paradoxic response to dexamethasone suppression, and underwent trans-sphenoidal resection of a pituitary macroadenoma. Electron microscopy showed the tumor to be a Crooke's cell adenoma. Results of immunohistochemical staining were positive only for ACTH and beta-endorphin. The neuropsychiatric manifestations resolved after surgery.     

Late-presenting complete heart block after pediatric cardiac surgery

Late presenting complete heart block after pediatric cardiac surgery is a rare complication and its management is well defined once the initial diagnosis in made timely and appropriately. In this report we described a child who underwent atrioventricular septal defect repair with a normal sinus rhythm during the postoperative period, as well as during the first 2 years of follow up.She subsequently developed complete heart block with bradycardia that required insertion of a pacemaker. Here we discuss this unusual late-presenting complication, possible risk factors, and management.     

Reduced Stroke Risk After Parathyroidectomy in End-Stage Renal Disease: A 13-Year Population-Based Cohort Study

Research information on the risk of stroke in patients with dialysis-dependent end-stage renal disease (ESRD) who have undergone parathyroidectomy (PTX) is scant.We used a nationwide health insurance claims database to select all patients with dialysis-dependent ESRD age 18 years and older for the study population. Of the patients with ESRD, we selected 1083 patients who had undergone PTX between 1998 and 2006 as the PTX group and frequency-matched 1083 patients with ESRD by sex, age, years since the disease diagnosis, and the year of undergoing PTX as the non-PTX group.We used a multivariate Cox proportional hazards regression analysis to measure the risk of stroke for the PTX group compared with the non-PTX group after adjusting for sex, age, premium-based income, urbanization, and comorbidity.The mean follow-up periods were 6.08 and 5.38 years for the PTX and non-PTX groups, respectively. After adjusting for previously mentioned variables, significant risk reductions of stroke (adjusted hazard ratio = 0.57, 95% confidence interval = 0.41–0.79), particularly those of hemorrhagic stroke (adjusted hazard ratio = 0.34, 95% confidence interval = 0.20–0.57), with PTX were observed. Chronologically, the risk of stroke in the PTX group decreased in the second year after PTX and persisted for >3 years.PTX reduces the risk of stroke, particularly that of hemorrhagic stroke, in patients with dialysis-dependent ESRD. Other factors for risk reduction include sex (females), an age <65 years, and the presence of comorbidity.     

Risk of Ischemic Stroke in Patients With Gastric Cancer: A Nationwide Population-Based Cohort Study

Improvements in therapeutic modalities have prolonged the survival of gastric cancer patients. Comorbidities such as thromboembolic events that emerge as a result of disease complexities and/or treatments received have not been considered. The objectives of this study are to examine the relationship between gastric cancer and ischemic stroke, and to determine predictive risk factors.A nationwide population-based cohort study was conducted using data from the Taiwan National Health Insurance database. A total of 45,060 gastric cancer patients and non-cancer counterparts without antecedent stroke were recruited. Hazard ratios (HRs) and the cumulative incidence of ischemic stroke were calculated, and risk factors for ischemic stroke were assessed.Gastric cancer patients were associated with higher risk of ischemic stroke (HR 1.11, 95% confidence interval [CI] 1.03–1.19, P = 0.007), especially in participants younger than 65 years (HR 1.61, 95% CI 1.39–1.86, P < 0.001) and in female participants (HR 1.30, 95% CI 1.14–1.49; P < 0.001) when compared with the matched cohort. Independent risk factors of ischemic stroke in gastric cancer patients included age, hypertension, atrial fibrillation, dyslipidemia, and having received major surgery for gastric cancer.Our findings suggest the importance of stroke surveillance and prevention strategies in high-risk patients. Having received major surgery for gastric cancer is a significant risk factor in these patients.     

Usefulness of computed tomography scanning in the diagnosis of aortic prosthetic valve pannus

A 64-year old patient underwent aortic valve replacement with a bileaflet Medtronic Advantage prosthesis. Six years later, she presented with a recurrence of symptoms, at which time Doppler echocardiography revealed an obstruction of the aortic mechanical prosthesis (mean transvalvular gradient 35 mmHg). Both, transesophageal echocardiography and fluoroscopy failed to identify the mechanism of valve obstruction. Multislice computed tomography (CT) scanning provided indirect signs as well as direct evidence of pannus formation, which was confirmed at surgery. The value of CT scanning to assess the mechanism of aortic mechanical prosthesis obstruction is emphasized.