Cardiovascular prosthetic surgery: an analysis of cellular and molecular patterns underlying valve implantation failure.

Cardiac valves have a very complex microscopic architecture, this is due to the presence of many cell types and to the variegated stroma. From a morphological point of view, both physiological and pathological processes clearly show there to be an anatomic continuity between valve leaflets and perivalvular tissues; indeed, both component should be taken into consideration during thrombotic processes and in fibrous tissue formation. At present, morphological features are well known and classified, while little is known about histogenetic features: fibrous tissue formation and the role of the various types of adhesion molecules and cells which participate in this process still have to be fully elucidated. In the current study, we focused on the histological analysis of the pannus. In particular, we demonstrated that the true connective nature of the exuberant fibrous tissue was entirely composed of collagen/fibronectin fibre bundles and fibroblasts. Moreover we observed that the phlogistic infiltrates were composed of immune cells, mainly represented by CD4(+) and CD8(+) T lymphocytes. Finally we also tried to assess not only the degree of endothelial layer loss, but also the extent of revascularization in the exuberant fibrous tissue.

Evolution in the treatment of mediastinitis: single-center experience.

This study aimed to evaluate our 30-year experience in the treatment of deep sternal wound infection after cardiac surgery. Between 1979 and 2009, deep sternal wound infections occurred in 200 of 22,366 (0.89%) patients who underwent sternotomy. The study population was divided into 3 groups. In group A (62 patients; 1979-1994), an initial attempt at conservative antibiotic therapy was the rule, followed by surgery in case of failure. In group B (83 patients; 1995-2002), the treatment was in 3 steps: wound debridement and closed irrigation for 10 days; in case of failure, open dressing with sugar and hyperbaric treatment; delayed healing and negative wound cultures mandated plastic reconstruction. In group C (2002-2009), the treatment was based on early surgical debridement, vacuum application, and reconstruction using pectoralis muscle flap. Hospital mortality in group A was significantly higher than that in groups B and C. Hospital stay, time for normalization of white blood cell count and C reactive protein, and time for defervescence were significantly shorter in group C. In our experience, early surgical debridement and vacuum application followed by plastic reconstruction provided a satisfactory rate of healing and a good survival rate.

A Starr-Edwards mitral prosthesis after 44 years of good performance.

The Starr-Edwards caged-ball prosthesis has been widely used to replace cardiac valves. The Model 6120 mitral prosthesis was introduced on the market in 1965 to reduce the high incidence of ball variance and thromboembolism of the previous model. We report the case of a Starr-Edwards Model 6120 which had been in place for 44 years and was still well functioning with no apparent structural damage.

Role of myofibroblasts in vascular remodelling: focus on restenosis and aneurysm.

Myofibroblasts (MFs) are contractile cells deriving from a multiplicity of resident cells and/or circulating progenitors that are known to play a key role in wound healing. They were first discovered and analysed in the early 1970s in granulation tissue. Since their first identification, the role of MF and their mechanisms of differentiation have been highlighted in a number of diseases, including organ fibrosis and tumours, with particular attention devoted to the liver, kidney, and pulmonary fibrosis. The aim of this review is to summarize the current evidence for the role played by MFs in two frequent vascular diseases related to the remodelling of the vascular wall: the different forms of arterial restenosis and the most common forms of thoracic aortic aneurysm. The in-depth knowledge of the molecular pathways involved in MF differentiation, contraction, and survival/apoptosis could contribute to the identification of novel therapeutic strategies for anti-fibrotic and anti-remodelling therapy of vascular diseases in which these cells are involved.

Left ventricular hypertrophy in Caucasian master athletes: Differences with hypertension and hypertrophic cardiomyopathy.

AIM: To study, by conventional echocardiography, left ventricular remodelling and function in master athletes, hypertension and hypertrophic cardiomyopathy. METHODS: We studied 30 master athletes (MA; soccer players; mean age 43.9+/-5.9), 24 subjects with essential hypertension (HYP; 46.6+/-6), 20 patients with hypertrophic cardiomyopathy (HCM; 42.2+/-9) and 30 normal individuals (CG; 43.4+/-5). An integrated M-mode/two-dimensional echocardiographic analysis was performed to determine chambers dimensions, relative wall thickness (RWT) and left ventricular mass (LVM), indexed to height in meters raised to the power of 2.7 (LVM/h(2.7)). Cut-off levels for LVM/h(2.7) and RWT were defined to assess 4 different patterns of LV geometric remodelling. In addition, we measured indexes of global systolic performance and indexes of global diastolic function. RESULTS: LV wall thickness and LV end-diastolic dimensions were higher in MA than controls, but significantly lower than other groups. LVH/h(2.7) was increased in 79% of HYP and in 95% of HCM, but was within the normal limits in MA. LV geometry was normal in 22 out of 30 MA (73%), while the remaining (8 athletes, 27%) showed a concentric remodelling. Systolic function (FS and EF) was normal in MA, but was slightly reduced in HYP and increased in HCM. Analysis of diastolic function showed an abnormal relaxation pattern in all HYP and 95% of HCM, but was normal in all MA. The ratio between peak filling rate and stroke volume (PFR/SV), a relatively independent index of diastolic function, was significantly greater in hypertensive patients with normal LV remodelling compared to those without it (4+/-0.39 vs. 4.91+/-0.19; P = 0.0002). CONCLUSION: MA showed lower values of wall thickness, LV dimensions and LV mass compared with HYP and HCM. Despite an abnormal remodelling, all the athletes showed a normal systolic and diastolic function. The differential diagnosis between MA, HYP and HCM is feasible by accurate, comprehensive standard Doppler echocardiography.

Transthoracic Doppler echocardiography of mammary artery grafts to assess graft function.

BACKGROUND: Transthoracic Doppler echocardiography of internal mammary artery grafts (MAGs) has been tested by the supraclavicular approach, but little information is available about the parasternal approach. OBJECTIVE: To evaluate the usefulness of parasternal transthoracic Doppler echocardiography to assess the patency of left and right MAGs. PATIENTS AND METHODS: Forty-eight patients with previous MAGs were divided into two groups on the basis of coronary angiography: 42 patients had patent MAGs and six patients had severe MAG stenosis. Doppler echocardiography of MAGs was performed on all patients, both at baseline and after low-dose dipyridamole infusion. Systolic and diastolic time-velocity integrals and their ratios were obtained, and MAG flow reserve was calculated. RESULTS: Patients with patent MAGs had a predominant diastolic flow, while a prominent systolic pattern was found in the presence of MAG stenosis. In patients with stenosis, baseline Doppler analysis showed a lower diastolic peak velocity (DPV) (P<0.01), diastolic time-velocity integral (P<0.05), and diastolic and systolic time-velocity integral ratios (both P<0.005), and a reduced MAG flow reserve (P<0.001). In the overall population, when adjusting for clinical variables, a multilinear regression analyis underscored MAG flow reserve (beta=0.38, P<0.01) and baseline DPV (beta=0.29, P<0.05) as independent determinants of MAG stenosis (cumulative R2=0.25, P<0.005). CONCLUSIONS: Doppler echocardiographic evaluation of MAGs is a reliable, noninvasive tool to assess MAG patency and functional status of the vessel. MAG blood flow reserve and baseline DPV are independent determinants of MAG stenosis.

Scanning electron microscopy of aortic medial changes in aortic ascending dilatation.

The study of cystic cavities and collagen fibers fragmentation is useful to for a better knowledge of pathogenesis and surgical therapy of medial ascending aortic degeneration. Thus, the aim of this study was to describe by scanning electron microscopy the surfaces and shape of the cysts, measure their area, and identify microcystic spaces related to this degenerative disease. Scanning electron microscopy analysis was performed in 16 out of 36 patients who underwent surgery for ascending aorta dilatation with associated aortic valve disease. The aortic medial wall showed a cribrose appearance at low magnification (x50-100) and the intima was effuse. At high magnification (x500-2000), small cavities (clefts) lined by normal or fragmented elastic fibers and large cavities (pseudocystes) with anfractuous borders lined by fragmented elastic fibers and smooth muscle cells were observed. Furthermore, in the outer media wall microvessels lined by endothelium were also observed. These changes were lacking or less pronounced in normal aorta. SEM allows one to better identify the pathological cavities and to differentiate them from microvessels. These pathological cavities are more numerous and larger in the convexity than in the concavity of the aorta in according to our previous morphological and morphometric findings in asymmetrical aorta dilatation.

Native versus primary prosthetic valve endocarditis: comparison of clinical features and long-term outcome in 353 patients.

BACKGROUND AND AIM OF THE STUDY: The study aim was to compare preoperative and intraoperative features, and long-term outcome of patients operated on for native (NVE) and primary prosthetic valve endocarditis (PVE). METHODS: Between January 1978 and December 2002, 258 patients (mean age 47.5 +/- 16 years) were referred for NVE, and 95 for PVE. Demographics, clinical preoperative conditions, indications to surgery, microbiological data, surgical pathology, early postoperative course and long-term outcome were compared via hospital chart review and outpatient clinic follow up. RESULTS: Female sex prevailed in the PVE group (49.5%) versus NVE (27.1%; p < 0.0001). Mitral valve involvement was more common in PVE (46.3% versus 24.8%, p = 0.0001), and multivalvular in 16.3% of NVE patients versus 4.2% of PVE (p = 0.001). Active endocarditis (80.6% versus 58.9%, p = 0.00004) and preoperative embolism (29.5% versus 11.6%, p = 0.0002) were significantly prevalent in the NVE group. Emergency operation (21.1% versus 10.5%, p = 0.009) and preoperative NYHA class IV or V (40% versus 19.8%, p < 0.0001) were significantly more frequent in PVE. Overall hospital mortality was 11.3% (n = 40), with 6.6% among NVE patients and 24.2% among PVE (p < 0.0001). Mean follow up (94% complete) was 5.8 +/- 5.3 years (6.0 +/- 5.5 years for NVE versus 5.1 +/- 4.6 years for PVE, p = 0.191), and total follow up was 1,707.85 patient-years. Actuarial survival at 1, 5, 10 and 15 years was respectively 91, 82, 67.5 and 48.8% in NVE, and 79.7, 64.2, 33.5 and 33.5% in PVE (p = 0.0016). A significantly lower survival in PVE versus NVE was found for the mitral site subgroup (p = 0.018), but not for the aortic site (p = 0.14). Actuarial freedom from reoperation for recurrent endocarditis at 1, 5, 10 and 15 years was 97.5, 91.4, 80.5 and 49.4% in NVE versus 90.8, 84.9, 59.4 and 43.9% in PVE (p = 0.015). CONCLUSION: PVE patients were older, presented with more compromised clinical conditions, and had worse early and long-term outcomes than NVE patients. PVE had a higher incidence of recurrence and worse prognosis, especially if the mitral valve was involved.

Does antegrade blood cardioplegia alone provide adequate myocardial protection in patients with left main stem disease?

BACKGROUND: The optimum route for cardioplegia administration in patients with severe coronary disease is still under debate. This study compared clinical, echocardiographic, and biochemical results in patients with left main stem disease treated with 2 different strategies of myocardial protection. METHODS: Between March 2000 and November 2002, 148 consecutive patients with left main stem disease undergoing coronary artery bypass grafting were divided into 2 groups according to the route of cardioplegia delivery: antegrade in 87 patients (group A) or antegrade followed by retrograde in 61 patients (group B). Electrocardiography, troponin I, MB-creatine kinase, and MB-creatine kinase mass were performed at 12, 24, 48, and 72 hours postoperatively. Echocardiography was performed preoperatively and before hospital discharge. Data were stratified in subgroups of patients with the following associated risk factors: left ventricular hypertrophy, diabetes, and right coronary stenosis. RESULTS: Groups were homogeneous in preoperative and intraoperative variables, apart from the higher incidence of unstable angina and severity of left main stem disease in group B. Hospital deaths, intensive therapy unit and hospital stay, perioperative acute myocardial infarction, and intraaortic balloon pump support were similar in both groups. Postoperative recovery of left ventricle ejection fraction and wall motion score index did not differ between the 2 groups. However, postoperative atrial fibrillation was higher in group A (P =.015), especially in patients with diabetes (P <.0001). Troponin I was significantly higher in group A from postoperative hours 12 to 72 (P <.01), and the same pattern was observed in patients with diabetes (P <.001), critical right coronary stenosis (P <.001), and left ventricle hypertrophy (P <.001). CONCLUSION: The combined route of intermittent blood cardioplegia allows better results in left main stem disease. Such data are confirmed even in risk subgroups.