Prosthetic heart valves: why biological?

The replacement of heart valves only became feasible after the development of the heart-lung machine in 1953. Two groups of prosthetic heart valves were subsequently developed: biological valves that do not require anticoagulation and mechanical valves that require life-long anticoagulation with Coumadin. The incidence of heart surgery and the demographics of patients who require heart valve surgery vary worldwide; these factors influence the choice of prosthetic valve for the individual patient and are briefly reviewed. Improved biological tissue-fixation methods are also increasing the durability of biological prosthetic valves and will further favor the implantation of biological valves in the future.     

Mechanical heart valves: are two leaflets better than one?

OBJECTIVE: We sought to compare the long-term clinical outcomes of patients who underwent isolated aortic valve replacement with single-disc and bileaflet mechanical heart valves. METHODS: From May 1975 through October 2001, 590 single-disc valves (7 models) were used for isolated valve replacement, and from November 1980 through July 2002, 1283 bileaflet valves (10 models) were used for isolated valve replacement. Detailed follow-up was performed to a maximum of 27.4 and 21.9 years with a total of 6872 and 5811 patient-years for single-disc valves and bileaflet valves, respectively. Survival and valve-related events were analyzed. RESULTS: Single-disc valves were mainly implanted from 1975 through 1995, whereas bileaflet valves were mainly implanted from 1987 through 2002; thus the years of concurrent use were 1987 through 1995. The bileaflet valve had a significantly lower explantation rate, whereas the single-disc valve had a significantly lower thromboembolism rate. No significant differences were detected in early mortality, long-term survival, and other valve-related complications. When limiting the comparison to the concurrent period of 1987 through 1995, no significant difference was detected in survival or in any valve-related complication. CONCLUSION: Single-disc and bileaflet valves provide similar clinical performance. The predominant use of bileaflet valves is not based on clinical outcomes.     

Are older patients with mechanical heart valves at increased risk?

Background. Controversy exists regarding the use of mechanical valves in older patients. Many authorities believe that the use of anticoagulants in the elderly is associated with an increased risk of warfarin-related complications. Therefore, we compared the results with mechanical valves in older patients to a cohort of younger patients.

Methods. Aortic (AVR) or mitral valve replacement (MVR) with a mechanical valve was performed in 1,245 consecutive patients who were followed prospectively. They were grouped by age (group 1, ≤ 65 years; group 2, > 65 years). The study groups consisted of AVR (group 1, 459 patients; group 2, 323 patients) MVR (group 1, 313 patients; group 2, 150 patients).

Results. The average age for the groups was: AVR (group 1, 51 years; group 2, 70 years; p = 0.03) and MVR (group 1, 53 years; group 2, 70 years; p = 0.03). For AVR the incidence of thromboembolism was 0.050 (group 1) and 0.038 (group 2) (p = 0.37) and the actuarial freedom from thromboembolism was 83.0% ± 3.0% and 86.5% ± 1.0%, respectively (p = 0.13). The incidence of bleeding after AVR was 0.021 for group 1 and 0.028 for group 2 (p = 0.49). For MVR the incidence of thromboembolism was 0.059 for group 1 and 0.051 for group 2 (p = 0.75) and the actuarial freedom from thromboembolism was 78.8% ± 3.0% and 75.4% ± 8.7%, respectively (p = 0.71). The incidence of bleeding after MVR was 0.020 for group 1 and 0.027 for group 2 (p = 0.62).

Conclusions. Mechanical valves perform well in selected older patients with no increased risk of bleeding or thromboembolism.     

Tissue-engineered vascular grafts: does cell seeding matter?

Purpose

Use of tissue-engineered vascular grafts (TEVGs) in the repair of congenital heart defects provides growth and remodeling potential. Little is known about the mechanisms involved in neovessel formation. We sought to define the role of seeded monocytes derived from bone marrow mononuclear cells (BM-MNCs) on neovessel formation.

Methods

Small diameter biodegradable tubular scaffolds were constructed. Scaffolds were seeded with the entire population of BM-MNC (n = 15), BM-MNC excluding monocytes (n = 15), or only monocytes (n = 15) and implanted as infrarenal inferior vena cava (IVC) interposition grafts into severe combined immunodeficiency/bg mice. Grafts were evaluated at 1 week, 10 weeks, or 6 months via ultrasonography and microcomputed tomography, as well as by histologic and immunohistochemical techniques.

Results

All grafts remained patent without stenosis or aneurysm formation. Neovessels contained a luminal endothelial lining surrounded by concentric smooth muscle cell layer and collagen similar to that seen in the native mouse IVC. Graft diameters differed significantly between those scaffolds seeded with only monocytes (1.022 ± 0.155 mm) and those seeded without monocytes (0.771 ± 0.121 mm; P = .021) at 6 months.

Conclusions

Monocytes may play a role in maintaining graft patency. Incorporation of such findings into the development of second-generation TEVGs will promote graft patency and success.     

Endomyocardial biopsy in heart transplantation: schedule or event?

Background

Endomyocardial biopsy is the gold standard to identify rejection after heart transplantation. Due to its invasiveness, discomfort, and difficult vascular access, some patients are not willing to accept routine scheduled biopsies years after heart transplantation. The purpose of this study was to identify whether there was a difference in outcomes among the scheduled versus event biopsy groups.

Methods

We studied 411 patients who underwent heart transplantation from 1987 to 2011, reviewing biopsy results and pathology reports. There were 363 patients who followed the scheduled biopsy protocol, and 48 patients who were assigned to the event biopsy group. We extracted data on biopsy results, rejection episodes, rejection types, and survival time.

Results

The 2481 reviewed biopsies over 24 years, showed most rejection episodes (86.4%) to occur within 2 years after heart transplantation. The rejection incidence was low (2.1%) at 3 years after transplantation. The major reason for an event biopsy was poor vascular access, such as tiny central vein or congenital disease without a suitable central vein. Event biopsy group patients were younger than schedule biopsy patients (19.7 years old vs 47.6 years old; P < .05). The 10-year survival rates were 64% among the event versus 53% among the scheduled biopsy group (P = .029). The 10-year rates of freedom from rejection were similar.

Conclusions

The rejection rate was low after 3 years; episodes occurred within 2 years. Although the long-term survival in the event group was better, they had a younger man age. The rejection and freedom from rejection rates were similar. As the rejection rate was low at 3 years after transplantation, we suggest that the event principle could be applied for biopsy at 3 years after heart transplantation.     

Inguinal hernia: mesh or no mesh in open repair?

The operative repair of inguinal hernias is the most common surgical procedure in general surgery. This review gives a survey of the current data on the "mesh or no mesh" question in open inguinal hernia surgery. The Cochrane Database Systematic Review of 2002 has the highest level of evidence. Five randomised controlled trials were published after the Cochrane analysis and in a retrospective study, 1,513,008 patients were summarised accordingly. According to these data, the incidence of postoperative complications (haematoma, seroma, wound infection and serious complications like bowel/vessel injury and bleeding) does not depend on the operative technique used. The implantation of meshes significantly decreases the overall recurrence rate, the occurrence of chronic pain and the time of return to normal activity, as compared to non-mesh techniques. The published data shows significant advantages for mesh techniques.     

Prostate cancer and coronary heart disease: correlation or coincidence?

A few past clinical and recent case-control studies of statin use, for example, in patients with and without prostate cancer have not demonstrated its potential for reducing or preventing the risk for this disease, and the potential for benefit may have been a confounding coincidence. Data from larger continuing and future studies will be needed to resolve this issue, but the recent data on cholesterol or dyslipidemia and risk increase or reduction with treatment are interesting, especially because of other potential improvements with therapy in nonprostate cancers. In addition, the finding that some available cancer treatments improve some parameters of the lipid profile is fascinating, and some cancer drugs are being used in a specific cardiovascular disease treatment setting to improve outcome. Even if CHD, dyslipidemia, and the treatment of these conditions has no role in preventing prostate cancer or its progression, what has been lost? CVD is still the leading cause of death of men, and a heart-healthy program for the patient concerned about prostate disease would reduce this primary cause of death. Patients would take a step forward in improving all-cause mortality. Recent data from surveys, however, continue to demonstrate that men have an inadequate understanding of cholesterol and heart disease. Crisis creates opportunity, and individuals working in urology have ample reasons not only to discuss the overall benefits of reducing lipid markers, but to improve cholesterol and CHD awareness as much as health professionals working in other fields of medicine. The marriage between general preventive medicine and urology seems to be inevitable, and in the authors' opinion, this merger will provide the foundation for novel research that could affect patients' lives dramatically.