Redo cardiac surgery in the era of percutaneous solutions: pattern of presentation and outcomes in a single tertiary care center

Introduction

The advent of new medical and interventional approaches has recently impacted on the referral for redo surgical operations. Little is known on current practice pattern and outcomes.

Purpose

We reviewed our institutional experience of 10 years (January 2011–December 2020) in a single university affiliated center to document frequency, outcome, and complications of the various types of redo procedures.

Methods

Retrospective analysis of a prospectively collected computed institutional database developed according to STS/EACTS recommendations.

Results

During study period 616 patients were referred for redo cardiac procedures, of which 129 patients underwent either medical or interventional procedures (75 thrombolysis, 22 valve-in-valve, 19 native mitral and or tricuspid percutaneous treatment, 13 paravalvular leakage devices), 459 patients were operated on, and 28 patients were denied any invasive treatment because of futility. Study group included these 459 surgical patients with a mean age of 62±12.7 years (octogenarians 5.6%, female sex 52.8%, diabetes 19.5%, chronic kidney disease 30%, urgent/emergent status 34.8%, third-time sternotomy 9.8%). The EuroSCORE II averaged 25.7±15.4%. Study group patients represented a nearly constant subgroup over the 6890 patients operated over this decade. Most frequent surgical procedures were valve operations, which were accomplished in 48.6% (223 pts), whereas isolated coronary bypass surgery was performed in 1.9% (9 pts) only. Valve thrombosis, mechanical prosthesis malfunction, paravalvular leakage, bioprosthetic failure and endocarditis (87% on prosthetic valve) were the most frequent indications. Combined procedures were performed in 15.2% (70 pts). Aortic root, ascending and arch replacement procedures were performed in 10.9% (50 pts, aortic dissection 7.8%). Cardiac transplantation in the setting of previous cardiac surgery was performed in 13.1% (60 pts including: previous conventional procedures [29 pts], mechanical circulatory devices [28 pts, 25 left ventricular assist device and 3 total artificial heart] and re-transplantation [3 pts]). Other procedures were performed in 10.2% (47 pts). Overall hospital mortality was 23,9%, rates of major complications were: surgical revision for bleeding 2,9%, Acute Kidney Injury (I/F) 17,4%, prolonged mechanical ventilation 12,9%, stroke 2,7%. Age, surgical priority, endocarditis, and heart failure represented the major independent predictors of morbidity and mortality.

Conclusions

Although percutaneous solutions are increasing their consensus, the rate of redo cardiac surgical procedures remained stable during the last 10 years. Outcomes are satisfactory despite increasingly complex patients features. Careful Heart Team evaluation is mandatory.

Funding Acknowledgement

Type of funding sources: None.

P371 1 YEAR OUTCOME OF BICARBON AORTIC MECHANICAL VALVE IN LOW–INR REGIMEN: RESULTS FROM SURE–AVR REGISTRY

Background

The drawback of using mechanical valve is lifelong anticoagulation use, and close monitoring is required to prevent postoperative complications, including thromboembolism and anticoagulation–related bleeding. Moderate anticoagulation after mechanical heart valve replacement has been proposed to reduce these risks. The present study aimed to evaluate the safety and feasibility of reduced oral anticoagulation after Bicarbon aortic mechanical valve replacement.

Methods

SURE–AVR is a propsective, multinational registry of patients undergoing aortic valve replacement. Between July 2018 and October 2020, among subjects undergoing AVR with Bicarbon valve in the SURE–AVR registry, 108 were assigned at discharge to low–INr regimen (international normalized ratio 1.5–2.5). Mean INr at discharge was 1.8+/–0.5 and 2.2+/–0.4 at 1 year. in–hospital and post–discharge outcomes up to 1 years were collected. The mean age was 55.5 +/–10.6 years old (range 25–82). Concomitant procedures included coronary artery bypass grafting (14.6%), mitral valve procedure (3.7%) and myectomy (1.9%). The follow–up duration averaged 1 year (361.8 +/– 258 days).

Results

No bleeding events were reported in the late follow up. The low–INR regimen did not affect the thromboembolism rates, since no stroke or transient ischemic attack were reported post–operatively at each time point. No in–hospital or late deaths were reported among the 108 subjects analyzed. In the early period (<30 days), three reinterventions occurred: two because of postoperative bleeding requiring thoracotomy and one due to pericardial effusion. In the late postoperative period two reinterventions with device explant occurred (one for non–structural valve dysfunction and one for endocarditis (1.2%).

Conclusion

The results of the SURE–AVr Registry demonstrated that the proposed Lower–INR Target is safe and feasible after Bicarbon aortic mechanical valve replacement. The low–intensity anticoagulation strategy is associated with a low risk of hemorrhagic events without any increase of thromboembolic complications.

MoDTC friction modifier additive degradation: Correlation between tribological performance and chemical changes

To get a better understanding of how the MoDTC additive works at the molecular level, correlation between its chemical behaviour in a bulk oil during thermo-oxidative degradation and its ability to reduce friction has been investigated.

Morphological and molecular characterization of healthy human ascending aorta

Knowledge of the characteristics of the normal human aorta has been constrained by lack of data on fresh aortic tissue, especially from healthy individuals. In this study, the gene expression and morphological characteristics of the thoracic ascending aorta (AA) of healthy organ donors have been evaluated, with the aim of providing reference data for the analysis of pathological AAs. We analysed by RT-PCR the differential expression of mRNAs coding for myocardin, smoothelin, alpha-smooth muscle actin (alpha-SMA) and the ED-A isoform of fibronectin (ED-A FN) in AA specimens from donors, integrating the results with immunohistochemical analysis of the same targets. Morphological and morphometric characteristics of the AAs were also evaluated. In order to account for possible regional variations in wall structure, the convexity of the aortic profile was compared to the concavity. No differences in gene expression occurred for any of the target genes between the concavity and the convexity of AAs. Immunohistochemistry revealed a different distribution of total FN and of its ED-A isoform in the media and in the intima. Smoothelin is expressed by the majority of cells in the media, with some positive cells also in the intima. Alpha-SMA is expressed in all the tunicae. Immunohistochemistry also revealed in the convexity of 50% of AAs the presence of discrete areas in the subadventital media with altered structure and cell morphology and with altered gene expression, resulting positive for ED-A FN and alpha-SMA, but not for smoothelin, indicating the occurrence of early lesions also in macroscopically healthy AAs.

Expression profiles in surgically-induced carotid stenosis: a combined transcriptomic and proteomic investigation

Vascular injury aimed at stenosis removal induces local reactions often leading to restenosis. The aim of this study was a concerted transcriptomic-proteomics analysis of molecular variations in a model of rat carotid arteriotomy, to dissect the molecular pathways triggered by vascular surgical injury and to identify new potential anti-restenosis targets. RNA and proteins extracted from inbred Wistar Kyoro (WKY) rat carotids harvested 4 hrs, 48 hrs and 7 days after arteriotomy were analysed by Affymetrix rat microarrays and by bidimensional electrophoresis followed by liquid chromatography and tandem mass spectrometry, using as reference the RNA and the proteins extracted from uninjured rat carotids. Results were classified according to their biological function, and the most significant Kyoro Encyclopedia of Genes and Genomes (KEGG) pathways were identified. A total of 1163 mRNAs were differentially regulated in arteriotomy-injured carotids 4 hrs, 48 hrs and 7 days after injury (P < 0.0001, fold-change > or =2), while 48 spots exhibited significant changes after carotid arteriotomy (P < 0.05, fold-change > or =2). Among them, 16 spots were successfully identified and resulted to correspond to a set of 19 proteins. mRNAs were mainly involved in signal transduction, oxidative stress/inflammation and remodelling, including many new potential targets for limitation of surgically induced (re)stenosis (e.g. Arginase I, Kruppel like factors). Proteome analysis confirmed and extended the microrarray data, revealing time-dependent post-translational modifications of Hsp27, haptoglobin and contrapsin-like protease inhibitor 6, and the differential expression of proteins mainly involved in contractility. Transcriptomic and proteomic methods revealed functional categories with different preferences, related to the experimental sensitivity and to mechanisms of regulation. The comparative analysis revealed correlation between transcriptional and translational expression for 47% of identified proteins. Exceptions from this correlation confirm the complementarities of these approaches.

Perioperative optic neuropathy following off-pump coronary artery bypass grafting

Visual loss from ischemic perioperative optic neuropathy (PON) rarely occurs during the postoperative period of patients undergoing cardiac surgery. Since the first description, PON has been associated with cardiopulmonary bypass (CPB), being some CPB-related complications and epiphenomena considered the causes of such terrible complication. In particular, the risk for micro-embolization during aortic cannulation and clamping, the CPB-related inflammatory response, the hemodilution and the hypothermia during CPB could be responsible of PON. However, some cases of PON still remain idiopathic. We report here a very rare case of PON following off-pump surgery in a patient with severe coronary disease and multiorgan comorbidities. The case reported opens the debate on the potential mechanisms underlying PON, other than cardiopulmonary bypass.

Myocardial protection with insulin cardioplegia: who can really benefit?

AIM

The aim of the study was to evaluate the effects on myocardial protection of insulin-enriched warm blood cardioplegia (IWBC) in coronary artery bypass grafting (CABG) and in subgroups of patients with associated cardiac co-morbidities.

METHODS

Between May 2000 and December 2002, 268 consecutive patients underwent CABG with warm blood cardioplegia (group A) or IWBC (10 UI/L) (group B). Hospital outcome, ECG, echocardiography and biochemical markers of ischemia were compared. Differences between subgroups of patients with unstable angina (UA), ventricular hypertrophy (VH) and diabetes were assessed.

RESULTS

Hospital mortality, incidence of postoperative myocardial infarction and low output syndrome, IABP requirement, postoperative atrial fibrillation, in-hospital and in-ITU stay, postoperative recovery of left ventricular function and enzyme leakage did not show differences between the 2 groups; inotropic support was lower in IWBC. Moreover, patients with UA and IWBC showed a lower troponin I (TnI) (12 h: 0.82+/-0.57 ng/mL vs 2.56+/-1.18, P < 0.0001; 24 h: 0.71+/-0.64 vs 2.16+/-1.52, P < 0.0001; 48 h: 0.69+/-1.13 vs 1.79+/-1.43, P = 0.001; 72 h: 0.44+/-0.83 vs 1.01+/-1.02, P = 0.001), lower incidence of atrial fibrillation (4.2% versus 60.6%; P < 0.0001) and intraoperative defibrillation (0% versus 27.3%; P = 0.007). Furthermore, patients with VH treated with IWBC showed lower level of TnI (12 h: 0.41+/-0.32 ng/mL vs 2.93+/-0.67, P < 0.0001; 24 h: 0.37+/-0.45 vs 2.40+/-1.28, P < 0.0001; 48 h: 0.22+/-0.18 vs 1.95+/-1.33, P < 0.0001; 72 h: 0.12+/-0.12 vs 1.31+/-1.56, P < 0.0001), lower atrial fibrillation (6.5% vs 48%, P < 0.0001) and ventricular defibrillation (0% vs 20%, P = 0.011).

CONCLUSIONS

Insulin addiction to blood cardioplegia does not show any benefit in the global population and in diabetics; nevertheless, better myocardial protection can be demonstrated in patients with unstable angina and left ventricular hypertrophy.

Myocardial protection in diabetics with left main stem disease: which is the best strategy?

AIM

Diabetes mellitus is a well known risk factor for extensive coronary disease. The optimal route for cardioplegia administration in patients with severe ischaemic heart disease undergone surgery, especially with left main stem disease (LMSD) is still under debate. Aim of the study is to compare 2 different strategies of myocardial protection in diabetics with LMSD.

METHODS

Between January 2000 and June 2003 90 consecutive patients with type II diabetes mellitus and LMSD undergoing isolated myocardial revascularization were divided into 2 groups according to the route of cardioplegia delivery: antegrade in 45 patients (group A), antegrade followed by intermittent retrograde in 45 (group B). ECG, Troponin I, MB-CPK, MB-CPK mass were performed at 12, 24, 48, and 72 hours postoperatively. Echocardiography was performed preoperatively and before hospital discharge.

RESULTS

Groups were homogeneous in preoperative and intraoperative variables, apart from higher incidence of unstable angina and longer cardiopulmonary bypass time in Group B and hypertension in Group A. Hospital deaths, in intensive care units (ITU) stay, perioperative acute myocardial infarction, intra-aortic balloon pump support, postoperative recovery of left ventricle ejection fraction and wall motion score index were similar in both groups. In hospital stay proved shorter in group B (p=0.002), whereas postoperative atrial fibrillation was higher in group A (p<0.001), as postoperative inotropic support (p=0.006). Troponin I proved significantly higher in group A from the 12 degrees to the 72 degrees postoperative hour (p<0.0001).

CONCLUSIONS

Despite major in hospital end-points did not differ with strategy of cardioplegia administration, combined route of intermittent blood cardioplegia allows better biochemical and perioperative results in diabetics with LMSD.

The risk of stroke following CABG: one possible strategy to reduce it?

OBJECTIVE

Stroke remains a devastating complication of coronary artery bypass grafting (CABG): we evaluated whether a more aggressive diagnostic and therapeutic approach can reduce its incidence.

METHODS

Between January 1998 and January 2002, 1388 consecutive patients underwent isolated on pump CABG with blood cardioplegia. Among the first 627 patients (Group A), Echo-Doppler study (DS) was performed only in selected patients (58) with history of cerebrovascular disease (CVD) and/or carotid bruit; in 761 patients (Group B), DS was performed routinely. Carotid endarterectomy (CEA) was performed in 45 patients in Group A associated to CABG during cardiopulmonary bypass (CPB) and in 90 patients in Group B under local anaesthesia before CABG. Brain CT scan was performed in all cases with postoperative neurological symptoms.

RESULTS

The two groups were homogeneous for age, sex, associated diseases, history of CVD, number of graft and CPB time. There were no differences in terms of hospital mortality between Group A (22/627: 3.5%) and Group B (21/761: 2.75%); p=0.5. Postoperative stroke was observed in 24/627 (3.82%) patients of Group A and in 2/761 (0.26%) of Group B (p<0.001). Hospital mortality for stroke was higher in Group A (12/627: 1.91%) than in Group B (0/761; p<0.001) as well as the incidence of non-fatal stroke (Group A 12/627: 1.91% versus Group B 2/761: 0.26% p=0.006).

CONCLUSIONS

Preoperative DS, performed in all cases of CABG, followed by CEA under local anaesthesia in patients with critical carotid stenosis reduces the incidence of postoperative stroke.

Pilot study on prevention of lung injury during surgery for type A acute aortic dissection: no evident improvements with celsior flushing through the pulmonary artery

OBJECTIVE

Postoperative respiratory failure is a frequent and serious complication in patients with type A acute aortic dissection. Experimental evidence suggests that pulmonary artery perfusion using hypothermic protective solutions helps prevent lung injury. The aim of this pilot prospective study was to evaluate the effect of pulmonary artery flushing during selective cerebral perfusion (SCP) on lung function.

METHODS

Twenty patients referred for acute type A aortic dissection, who were free from preoperative respiratory dysfunction, were assigned prospectively and alternately to two treatment groups. Pulmonary flushing was performed during SCP in group P (10 patients), while conventional Kazui technique was applied in group N (10 patients). Lung perfusion consisted of single-shot hypothermic pulmonary artery flush with Celsior. Lung function was evaluated by intubation time, scoring of chest radiograms at 12 hours after CPB, and PaO2/FiO2 assessed from immediately before surgery to 72 hours after termination of cardiopulmonary bypass.

RESULTS

Incidence of pre, intra and post operative determinants of lung dysfunction proved homogeneous in both groups. Lung oxygenation function showed a marked post operative decline followed by a slow improvement in both groups. Analysis of respiratory ratios did not disclose significant differences even though the flushed group had a better performance in all study patients. The incidence of prolonged ventilator support (longer than 72 hours) (30% vs 20%, p = NS) and severity of x-ray pulmonary infiltrate score were comparable (mean score 1.7 +/- 0.71 vs 1.6 +/- 0.68, p = NS).

CONCLUSIONS

Pulmonary artery flushing with Celsior solution does not seem to provide an effective preservation of lung function.

Midterm results of a prospective randomized comparison of two different rabbit-antithymocyte globulin induction therapies after heart transplantation

This prospective randomized study compared the effects in heart transplant recipients of thymoglobulin and ATG, two rabbit polyclonal antithymocyte antibodies available for induction therapy. Among 40 patients (29 men and 11 women, mean age: 40.7 +/- 14 years) undergoing orthotopic heart transplantation, 20 were randomly allocated to receive induction with thymoglobulin (group A) and 20 to ATG-fresenius (group B). Comparisons between the two groups included early posttransplant (6 months) incidence of acute rejection episodes (grade >/= 1B), bouts of steroid-resistant rejection, time to first rejection, survival, graft atherosclerosis, infections, and malignancies. The study groups displayed similar preoperative and demographic variables. No significant difference was found with regard to actuarial survival (P =.98), freedom from rejection (P =.68), number of early rejections > 1B (P =.67), mean time to first early cardiac rejection (P =.13), number of steroid-resistant rejections (P =.69). Cytomegalovirus reactivations were more frequent among group A (65%) than group B (30%; P =.028). New infections due to cytomegalovirus occurred only in group A (four patients; 20%; P =.05). No cases of malignancies were observed at a mean follow-up of 32.8 +/- 8.9 months. Although thymoglobulin and ATG showed equivalent efficacy for rejection prevention, they have different immunological properties. In particular, thymoglobulin seems to be associated with a significantly higher incidence of cytomegalovirus disease/reactivation.

Evolving practice patterns in heart transplantation: a single-center experience over 15 years

This analysis is a retrospective characterization of evolving patterns in donor and recipient risk factors for early and late outcomes (survival and freedom from rejection) along with determinants of hospital and 1-year mortality after heart transplantation over a 15-year experience in a single center. Profiles and outcomes were evaluated for procedures performed between 1988 and 1995 (group A, n = 105) versus 1996 and 2003 (group B, n = 218). The following parameters were considered: pretransplant diagnosis, recipient age UNOS status, donor age, total postretrieval ischemic time, donor/recipient size match, and degree of myocardial necrosis at biopsy. Recipients in group B were significantly more compromised as demonstrated by UNOS status (11.4% vs 19.3%; P =.05) and pretransplant pulmonary vascular resistance (2.3 +/- 1.5 vs 3.1 +/- 1.5; P =.04). Marginal donors were more frequently used for group B procedures (21.9% vs 47.7%; P <.0001). Outcomes were significantly more favorable among group B patients in terms of hospital mortality (18.1% vs 10.6%; P =.046), and 1- and 5-year actuarial survival (72.4% vs 83.4%, 60% vs 73.3%, respectively; P =.006). Analysis of the causes of death disclosed a significant reduction in fatal events due to graft failure and acute rejection in group B. No difference emerged with regard to actual freedom from acute rejection. Determinants of hospital mortality were pretransplant diagnosis, UNOS status, donor age, and cardioplegic solution. Transplant era, recipient age, infectious episodes, and ischemic necrosis at biopsy were risk factors for 1-year mortality. We conclude that despite extensive usage of marginal donors and selection of worse candidates, significantly better outcomes were achieved due to improvements in global management strategies.

Risk factors for pacemaker implantation following aortic valve replacement: a single centre experience

OBJECTIVE

To identify perioperative clinical predictors of permanent pacemaker implantation following aortic valve replacement.

DESIGN AND PATIENTS

Prospective cohort study on 276 patients submitted for aortic valve replacement: 267 patients (mean (SD) age, 57.5 (14) years) with no conduction disturbances, and nine patients (67.7 (5) years) with severe conduction disturbances requiring permanent pacing; 65 perioperative variables (38 preoperative, eight intraoperative, and 19 postoperative) were considered.

RESULTS

Nine patients (3.2%) had irreversible second or third degree atrioventricular (AV) block requiring permanent pacing. Risk factors for permanent pacing identified by univariate analysis were: preoperative: additional valvar disease, aortic regurgitation, myocardial infarction, pulmonary hypertension, anaemia, use of digitalis; intraoperative: cardiac arrest; postoperative: cardiac arrest, conduction disturbances, electrolytic imbalance, angiotensin converting enzyme inhibitor use. Multivariate logistic regression analysis identified preoperative aortic regurgitation (p < 0.005; odds ratio (OR) 6.6, 95% confidence interval (CI) 1.6 to 12.2), myocardial infarction (p < 0.0005; OR 15.2, 95% CI 6.3 to 19.9), pulmonary hypertension (p < 0.005; OR 12.5, 95% CI 3.2 to 18.3), and postoperative electrolyte imbalance (p < 0.01; OR 4.5, 95% CI 1.3 to 6.4).

CONCLUSIONS

Irreversible AV block requiring permanent pacemaker implantation is an uncommon condition following aortic valve replacement. Previous aortic regurgitation, myocardial infarction, pulmonary hypertension, and postoperative electrolyte imbalance should be considered in order to identify patients at increased risk for advanced AV block.

Does priming implementation with low-dose albumin reduce postoperative bleeding following cardiopulmonary bypass?

This study aimed to assess whether low doses of albumin in the priming solution for cardiopulmonary bypass (CPB) reduce postoperative bleeding. Three-hundred and seventy-seven patients undergoing CPB were retrospectively assigned to group A (154 patients, CPB primed with 20 ml/kg Ringer Lactate solution + 0.75 mg/kg albumin 20%) and group B (223 patients with 20 ml/kg Ringer Lactate). A significant difference was found in terms of reoperations for bleeding (group A 0/154 versus group B 9/223; P=0.033). The mean number of blood derivatives transfused per patient was higher in group B than in group A (P<0.001). Platelet count after CPB was higher in group A than in group B (175 +/- 52x10(3)/microl versus 131 +/- 70x10(3)/microl; P=0.045). The amount of postoperative bleeding was 525 ml versus 680 ml at 24 hrs (P<0.001), 819 ml versus 1102 ml at 48 hrs, (P<0.001), 963 ml versus 1294 ml at 72 hrs, (P<0.045) (group A versus group B respectively). Crystalloid priming with low-dose albumin reduces postoperative bleeding.

Initial clinical and hemodynamic experience with Edwards MIRA mechanical bileaflet valve

AIM

An enhanced bileaflet valve, the Edwards MIRA feminine Mechanical Valve became available in 1998. Favorable hydrodynamic features and a redesigned sewing ring encouraged us to implant this device in indicated patients. Hemodynamics and clinical performance parameters were evaluated.

METHODS

Between February 1998 and October 1999, 338 patients (171 males, 167 females) underwent native valve replacement with a MIRA prosthesis. Mean age 56.6+/-13.6 years, 320 patients were in NYHA class III/IV. Sixty-seven patients had echocardiographic examinations. Standard cardiopulmonary bypass was employed utilizing institutionally accepted implantation techniques. Aortic valve replacement was performed in 163 patients, mitral valve replacement in 134 patients, 35* double valve replacements and 1 triple valve replacement.

RESULTS

Follow-up is 98% complete. Mean follow-up is 6.9+/-3.3 months (178.2 patient years). There were no operative deaths. Four early deaths were seen (1.18%). Late deaths reported in 12 patients. Linearized rate of late mortality was 6.7% per patient year (ppy). Overall actuarial survival at 13 months is 92.2%. Mean gradients and Effective Orifice Areas (EOA's) are comparable to other bileaflet valves. Linearized rates for valve-related complications was 4.49% ppy. Only 5 transient thromboembolic events (TE = 2.81% ppy) and 3 non-structural valve dysfunction events (NSVD = 1.68%) were seen. No reports of bleeding events, prosthetic endocarditis, valve thrombosis or structural valve deterioration. One patient required mitral valve reoperation for perivalvular leak.

CONCLUSIONS

Short-term hemodynamic and clinical results are comparable to other bileaflet valves. The sewing ring is non-obstructive, compliant with smoother needle penetration. Early clinical results are encouraging, follow-up should be continued.

Surgical injury of rat arteries: genetic control of the remodelling process

OBJECTIVES

Remodelling and restenosis are complex biological processes responsible for bypass and percutaneous transluminal coronary angioplasty failures which are likely to affect many hundreds of genes. We evaluated the effectiveness of topically applied antisense oligonucleotides in reducing the translation of the messenger RNA for the transcription factor c-myc and in reducing stenosis.

METHODS

Surgery was performed under sterile conditions; 60 Wistar-Kyoto male rats were anaesthetized by ketamine. The carotid arteries were isolated through a median incision in the anterior neck region. At the same point, 0.5 mm longitudinal incisions were performed. Haemostasis was obtained by an adventitial 8.0 stitch. Thirty animals were given 150 microg of c-myc antisense oligonucleotide (Group A) while the other 30 animals received 150 microg of c-myc control sense oligonucleotide (Group B). Oligo molecules were locally applied through 100 microl of 20% pluronic gel. Rats were sacrificed at 30 days; carotid arteries were explanted and stained. Qualitative histological analysis was performed in all cases; serial sections were made every 25 micro in seven consecutive rats for each group. Morphometric analysis was also performed, luminal and medial area values recorded and the ratio between the two areas calculated. Data from each animal were compared with the corresponding contralateral carotid artery and expressed as mean+/-standard deviation. Statistical comparison between the two groups was carried out by one-way ANOVA text.

RESULTS

Qualitative histological analysis showed marked remodelling with complete disarray of vessel wall, neointima accumulation and evidence of elastic fibres in the adventitia of all animals of Group B versus Group A. Morphometric analysis showed a significant reduction in the lumen area in Group A animals together with increased values of the medial area versus Group B animals. In addition, the ratio between the lumen and medial area was significantly higher in Group A than in Group B (2.61+/-0.18 versus 1.14+/-0.33, P<0.0001).

CONCLUSIONS

c-myc antisense oligonucleotides applied intraoperatively can reduce post-operative stenosis.

Medial degeneration does not involve uniformly the whole ascending aorta: morphological, biochemical and clinical correlations

OBJECTIVE

To investigate whether and how the severity of medial degeneration (MD) lesions varies along the circumference of the dilated intrapericardial aorta.

METHODS

Two groups of aortic wall specimens, respectively harvested 1cm distal to the non-coronary (NC) sinus (right postero-lateral wall) and to the right coronary sinus (anterior wall) in 22 patients undergoing surgery for dilatation of the intrapericardial aorta associated with aortic valve disease, were separately sent for pathology, morphometry and ultrastructural examination. MD lesions found at histology were classified into three degrees of severity. MD mean degree and morphometric findings in postero-lateral ('NC') and anterior ('coronary') specimens were compared by paired t-test. Correlation between degree of aortic dilatation at echocardiography and severity of MD was assessed separately for each of the two groups of specimens. After the preliminary results of the morphological study, we decided to send the specimens for biochemical investigation of protein electrophoretic patterns. This was performed in the last seven patients of this series.

RESULTS

At histology, MD was found in all cases. A higher mean MD degree was found in the NC group (2.59+/-0.50 versus 1.59+/-0.67 in the coronary group; P<0.001). At morphometry, normal smooth muscle cells in the NC specimens were significantly reduced (P=0.012) and the length (P=0.011) and number (P=0.015) of elastic fibres reduced and increased, respectively. Correlation between aortic ratio and MD degree was significant in the NC specimens (P<0.001), not in the coronary ones (P=0.227). Quantitative differences between coronary and NC proteins from the same patient and between coronary proteins from different patients were found at electrophoresis. However, at this stage of the study, the sample was too small to allow for the identification of proteins involved in those differences.

CONCLUSIONS

MD lesions in dilated intrapericardial aorta are more severe in the right postero-lateral wall area, likely due to haemodynamic stress asymmetry.

Gene expression and morphological changes in surgically injured carotids of spontaneously hypertensive rats

The expression profiles of genes involved in cell proliferation, differentiation and programmed death were investigated in carotids of spontaneously hypertensive rats (SHR) treated with a model of surgical injury that mimics events occurring during arterial grafts, endarterectomy and organ transplantation. The mRNA level of the c-myc, angiotensin II receptor 1 (AT1), Rb/p105, Rb2/p130, Bcl-2 and Bax-alpha genes was assessed by a semi-quantitative reverse transcription-polymerase chain reaction (RT-PCR) technique at different times up to 48 h after injury, while the morphological changes were evaluated 30 days after injury. The proliferation marker c-myc increases almost immediately, peaks after 4 h and returns to basal levels after 24 h; the AT1 receptor mRNA reaches its maximal level 48 h after injury. The level of cell cycle exit markers Rb/p105 and Rb2/p130 gradually decreases after injury. The apoptosis marker Bcl-2/Bax-alpha ratio shows a significant reduction only 4 h after injury, resuming the initial value after 24 and 48 h. Morphological analysis reveals that surgical injury in SHR induces adventitial and medial constrictive remodeling changes rather than intima proliferation as in balloon angioplasty. Both molecular and histological data show substantial differences with respect to normotensive rats.

Long Term Clinical and Echocardiographic Results of Isolated Aortic Valve Replacement in Elderly Patients

Results after isolated aortic valve replacement with bileaflet prostheses in patients over 70 years old were reviewed.

One-hundred-twenty-eight elderly patients were operated on between January 1988 and January 2000. Patients with associated heart disease were excluded from the study. Preoperative data, early and late postoperative mortality, all valve related complications and data concerning anticoagulation status were recorded.

Hospital mortality was 9.3%. Mean follow-up time was 60.98±2.23 months. Twelve-year actuarial survival was 69.6±0.08%. Valve related and anticoagulation related complication rates (0.8% and 1.6% respectively) and actuarial freedom (99±0.009 both) were low, as well as the mean interval between consecutive INR checks (18.39±1.90 days) and the mean INR value (2.17±0.135). Late echocardiographic results showed low postoperative mean transprosthetic gradients (15.48±0.94).

Bileaftlet prostheses in the elderly can achieve excellent results with a low incidence of anticoagulation related complications and low risk of reoperation. Older age can no longer be considered a contraindication to bileaftlet prosthesis implant.

Long term clinical and echocardiographic results of isolated aortic valve replacement in elderly patients

Results after isolated aortic valve replacement with bileaflet prostheses in patients over 70 years old were reviewed. One-hundred-twenty-eight elderly patients were operated on between January 1988 and January 2000. Patients with associated heart disease were excluded from the study. Preoperative data, early and late postoperative mortality, all valve related complications and data concerning anticoagulation status were recorded. Hospital mortality was 9.3%. Mean follow-up time was 60.98 +/- 2.23 months. Twelve-year actuarial survival was 69.6 +/- 0.08%. Valve related and anticoagulation related complication rates (0.8% and 1.6% respectively) and actuarial freedom (99 +/- 0.009 both) were low, as well as the mean interval between consecutive INR checks (18.39 +/- 1.90 days) and the mean INR value (2.17 +/- 0.135). Late echocardiographic results showed low postoperative mean transprosthetic gradients (15.48 +/- 0.94). Bileaftlet prostheses in the elderly can achieve excellent results with a low incidence of anticoagulation related complications and low risk of reoperation. Older age can no longer be considered a contraindication to bileaftlet prosthesis implant.

Asymmetric medial degeneration of the intrapericardial aorta in aortic valve disease

BACKGROUND

A geometrical and functional asymmetry in the normal aortic root has been recently demonstrated. Whether the distribution of medial degeneration (MD) within the wall of the dilated ascending aorta in adult patients reflects such asymmetry, still has to be assessed.

METHODS

Nineteen patients with fibrocalcific aortic valve disease and dilatation of the intrapericardial aorta, without clinical signs and familiar history of primary elastic connective tissue disorders, underwent surgery. Biopsies (57 specimens) were taken in each patient from three areas of the ascending aortic wall distal to the three sinuses of Valsalva. MD lesions found at histology in each specimen were classified in three degrees. Comparisons were made between the three sites as to distribution of the three degrees and between one site and the other two as to incidence of the highest degree.

RESULTS

A mild degree of MD was found in 26 specimens (45.6%), moderate in 14 (24.6%), severe in 17 (29.8%). The distribution of the three degrees of MD changes was significantly different between one of the three studied wall areas and the other two (P<0.001): a significantly greater incidence of the highest degree of involvement in the aortic wall distal to the non-coronary sinus than in the wall areas corresponding to the coronary sinuses was found (P<0.001).

CONCLUSIONS

MD lesions in dilated intrapericardial aorta are more severe in the wall area distal to the non-coronary sinus, likely due to haemodynamic stress asymmetry.

Infective endocarditis of native cardiac valves: 22 years' surgical experience

BACKGROUND AND AIM OF THE STUDY

Most previous studies on surgery for endocarditis included cases of both prosthetic and native valve endocarditis (NVE), which clearly differ in their course and prognosis.

METHODS

Between February 1979 and July 2000, 199 patients underwent surgical treatment for NVE. The native valve was replaced in 185 patients, and repaired in 14. Correlations between previous heart disease and site of NVE, site and etiology, site and embolism, and etiology and extracardiac infection were analyzed. Viability of echocardiography to identify NVE features was compared with surgical inspection. Risk factors for hospital, late mortality and recurrence were assessed by multivariate analysis, including preoperative, operative and postoperative variables.

RESULTS

Streptococci were found in 52 cases (26.1%), mostly spreading from splanchnic (n = 10) and cutaneous (n = 9) infections; Staphylococci were found in 43 cases (21.6%), mostly from cutaneous foci (n = 20). Tricuspid valve endocarditis was due to Staphylococcus sp. in all documented cases (11/15; p <0.001), while Streptococcus sp. predominated in the mitral (p = 0.026) position. Echocardiography was reliable in identifying anatomic features of NVE, except for periannular abscess (13 versus 31 found at surgery; p <0.001). Hospital mortality was 6% (n = 12): preoperative NYHA class IV (p = 0.034) and emergency surgery (p = 0.001) were significant predictors of mortality. Average follow up was 57.2+/-4.4 months and was 96.3% complete. There were 27 late deaths (15%). Actuarial survival was 75.7% at 10 years and 60.3% at 20 years. Low social status (p = 0.022), diabetes mellitus (p = 0.003), fever at time of surgery (p = 0.041) and persistent postoperative fever (p = 0.0002) were predictors for late mortality. Endocarditis recurred in 28 patients (15.5%), with 74.1% freedom at 10 years and 68.7% at 20 years. Drug abuse (p = 0.001), mitral endocarditis (p = 0.002), positive blood cultures (p = 0.0003), homograft implantation (p = 0.0012) and persistent postoperative fever (p <0.0001) were significant predictors for recurrence.

CONCLUSION

Preoperative conditions of patients with NVE significantly affect early and long-term outcomes. Prognosis is worsened by delayed diagnosis and operation during the active septic process.

Recurrent infective endocarditis: a multivariate analysis of 21 years of experience. arenzul@tin.it

BACKGROUND

To evaluate which variables predict recurrence of endocarditis after surgical treatment, we reviewed our 21-year experience.

METHODS

Between January 1979 and May 2000, 308 consecutive valve replacement procedures for infective endocarditis were performed in 271 patients. Univariate and multivariate time-related analyses were performed to retrospectively evaluate the role of the following variables in the development of recurrent postoperative endocarditis: gender, site of endocarditis, previous valve disease, drug abuse, diabetes, positive valve/blood cultures, sepsis, perivalvular involvement, previous embolic events, type of replacement device, and persistent postoperative fever.

RESULTS

Clinical and echocardiographic follow-up was 97.36% complete, mean follow-up time was 53.2+/-3.4 months. Recurrent endocarditis developed in 58 cases (22.5%). Variables predicting recurrence were prosthetic endocarditis (p = 0.00001), positive valve culture (p = 0.0039), and persistence of fever at the seventh postoperative day (p = 0.000001).

CONCLUSIONS

Correct protocols of antibiotic therapy guided by microbiology may reduce the incidence of recurrent endocarditis to allow for surgery on sterile tissues and to prevent prosthetic infection. Recurrence rate is not affected by the choice of valve substitute, but can be prevented by complete surgical debridement.

Risk predictors of paroxysmal atrial fibrillation following aortic valve replacement

BACKGROUND

Atrial fibrillation (AF) is the most frequently encountered arrhythmic complication associated with cardiac surgery. The aim of this paper was to identify the clinical predictors of AF occurrence following aortic valve replacement.

METHODS

Three hundred and two patients were included in this study and divided into two groups according to the absence (SR group, 243 patients, mean age 55.6 +/- 15 years) or the evidence (AF group, 59 patients, mean age 63.8 +/- 11 years) of post-aortic valve replacement AF. Sixty-five perioperative variables (37 preoperative, 8 intraoperative and 20 postoperative) were considered.

RESULTS

Post-aortic valve replacement paroxysmal AF occurred in 59 out of 302 patients (19%). At univariate analysis, post-aortic valve replacement AF was associated with advanced age, left atrial enlargement, preoperative episodes of paroxysmal AF, the use of a warm blood cardioplegic solution and normothermia, administration of inotropic agents, prolonged assisted ventilation but also with postoperative acidosis, electrolyte imbalance and atrioventricular and intraventricular conduction disorders. Stepwise forward multivariate logistic regression analysis identified age (p = 0.002, odds ratio--OR 1.04), left atrial enlargement (p = 0.004, OR 2.6), a prior history of paroxysmal AF (p = 0.0003, OR 10.9), and postoperative electrolyte imbalance (p = 0.01, OR 2.3) as independent correlates of AF, whereas the use of hypothermia appeared to be a protective factor (p = 0.0004, OR 0.26).

CONCLUSIONS

According to our findings, post-aortic valve replacement AF seems to be associated with well-defined anatomical and electrical substrates generated by advanced age, increased left atrial dimensions, and a possible electrical remodeling consequent to prior repetitive episodes of paroxysmal AF. On these grounds, external factors such as postoperative electrolyte imbalance might enhance atrial ectopic activity and trigger postoperative sustained tachyarrhythmias, while the use of hypothermia might allow for better protection of the atrial myocardium against intraoperative ischemia.

Surgery of rheumatic mitral stenosis: comparison of different techniques

OBJECTIVE

The breakthrough of percutaneous transvenous mitral commissurotomy (PTMC) has dramatically changed the indications for the surgical treatment of rheumatic mitral stenosis over the last decade. No recent studies comparing long-term results of PTMC, open mitral commissurotomy (OMC) and mitral valve replacement (MVR) with bileaflet prostheses are available in medical literature.

METHODS AND RESULTS

Between January 1991 and December 1997, 313 patients with pure and isolated rheumatic stenosis were treated in our department. One hundred and eleven patients underwent PTMC, 82 OMC and 120 MVR. There was no statistical difference (p>0.05) between the mortality rates of the three groups of patients. No cases of hospital mortality were observed in the patients who underwent PTMC and OMC, whereas two patients (1.6%) died within 30 days after MVR. Seven year actuarial survival results are: 95.41+/-2(SE)% (PTMC), 98.05+/-1% (OMC) and 92.82+/-33% (MVR) (p=NS). Freedom from embolism was 98.78+/-1% in PTMC, 98.78+/-1% in OMC and 92.52+/-2% in MVR (p>0.05); freedom from reoperation was 88.43+/-8% in PTMC, 96.35%+/-2% in OMC and 97.72+/-1% in MVR (p>0.05). The mean NYHA class at the end of follow-up was lower in OMC (1.14+/-0.3) versus PTMC (1.39+/-0.6) and MVR (1.41+/-0.71) (p=0.001).

CONCLUSIONS

Even though conservative techniques are the first option to consider in treating mitral valve stenosis, valve replacement with bileaflet prostheses no longer represents a limiting factor to survival and quality of life.

Deep sternal wound infection: the role of early debridement surgery

OBJECTIVE

This retrospective chart review study aimed to evaluate whether a more aggressive staged approach can reduce morbidity and mortality following post-cardiotomy deep sternal wound infection.

METHODS

Between 1979 and 2000, 14620 patients underwent open heart surgery: mediastinitis developed in 124 patients (0.85%). Patients were divided in two groups: in 62 patients (Group A) (1979-1994) an initial attempt of conservative antibiotic therapy was the rule followed by surgical approach in case of failure; in 62 patients (Group B) (1995-2000) the treatment was staged in three phases: (1) wound debridement, removal of wires and sutures, closed irrigation for 10 days; (2) in case of failure open dressing with sugar and hyperbaric therapy (11 patients, 17%); (3) delayed healing and negative wound cultures mandated plastic reconstruction (three patients, 4%). Categorical values were compared using the Chi-square test, continuous data were compared by unpaired t-test.

RESULTS

Incidence of mediastinitis was higher in Group B (62 out of 5535; 1.3%) than in Group A (62 out of 9085; 0.7%) (P=0.007). Mean interval between diagnosis and treatment was shorter in Group B (18+/-6 days) than in group A (38+/-7 days) (P=0.001). Hospital mortality was higher in Group A (19/62; 31%) than in Group B (1 out of 62; 1.6%) (P<0.001). Hospital stay was shorter in Group B (30.5+/-3 days) than in group A (44+/-9 days) (P=0.001). In Group B complete healing was observed in all the 61 survivors: 47 cases (76%) after Stage 1; 11 (18%) after Stage 2; three (4.8%) after Stage 3.

CONCLUSIONS

Although partially biased by the fact that the two compared groups draw back to different decades, this study showed that an aggressive therapeutic protocol can significantly reduce morbidity and mortality of deep sternal wound infection.

Standard 19mm St Jude aortic valves in patients with body surface less than 1.7m2

Although new models of bileaflet valves with improved orifice have been devised, aortic valve replacement with 19mm prostheses still raises concerns about long term effects of residual transprosthetic gradient.

We reviewed our experience with 19 mm standard model St Jude prostheses in 68 patients operated on between January 1983 and December 1995. Clinical late assessment was performed to evaluate the incidence of valve related complications. Postoperative echocardiography was performed to evaluate hemodynamic performance of the prostheses.

Mean body surface area was 1.66±0.14m2. Late postoperative peak gradient was 53.85±7.16 mmHg; mean gradient was 34.80±5.55 mm Hg; effective orifice area was 1.93±0.05 cm2. Thirteen-year actuarial survival has been 90.89 ± 0.6%; thirteen-year freedom from embolism 89.41 ± 0.7% and freedom from hemorrhage 98.25 ± 0.02%. No case of prosthetic endocarditis, thrombosis, or reoperation was observed during follow-up.

Standard 19mm St Jude aortic valves in patients with body surface less than 1.7m2

Although new models of bileaflet valves with improved orifice have been devised, aortic valve replacement with 19mm prostheses still raises concerns about long term effects of residual transprosthetic gradient. We reviewed our experience with 19 mm standard model St Jude prostheses in 68 patients operated on between January 1983 and December 1995. Clinical late assessment was performed to evaluate the incidence of valve related complications. Postoperative echocardiography was performed to evaluate hemodynamic performance of the prostheses. Mean body surface area was 1.66+/-0.14 m2. Late postoperative peak gradient was 53.85+/-7.16 mmHg; mean gradient was 34.80+/-5.55 mmHg; effective orifice area was 1.93+/-0.05 cm2. Thirteen-year actuarial survival has been 90.89+/-0.6%; thirteen-year freedom from embolism 89.41+/-0.7% and freedom from hemorrhage 98.25+/-0.02%. No case of prosthetic endocarditis, thrombosis, or reoperation was observed during follow-up.