Hans-Hinrich Sievers

Endovascular presence of viable Chlamydia pneumoniae is a common phenomenon in coronary artery disease.

OBJECTIVES We sought to examine coronary arteries for the presence of viable bacteria of the fastidious species Chlamydia pneumoniae. BACKGROUND The respiratory pathogen C. pneumoniae has been implicated in the pathogenesis of coronary artery disease (CAD). Previous studies have demonstrated an antichlamydial seroresponse to be a cardiovascular risk factor and coronary atheromata to contain chlamydial components in varying proportions. Endovascular demonstration of replicating bacteria is required to provide evidence for an infectious component in CAD and a rationale to discuss antimicrobial therapy. METHODS Myocardial revascularization was performed in 70 patients. Atherosclerotic lesions from 53 coronary endarterectomy and 17 restenotic bypass samples were cultured and subjected to nested polymerase chain reaction (PCR) for C. pneumoniae. Antichlamydial immunoglobulin G (IgG), IgA and IgM was examined by microimmunofluorescence. RESULTS Viable C. pneumoniae was recovered from 11 (16%) of 70 atheromata, and chlamydial deoxyribonucleic acid (DNA) was detected in 21 (30%) of 70 atheromata; 17 nonatherosclerotic control samples were PCR-negative (p < 0.01). Fifteen (28%) of 53 endarterectomy and 6 (35%) of 17 bypass samples were PCR-positive. DNA sequencing of six different PCR products did not reveal differences between coronary isolates and respiratory reference strains, suggesting that common respiratory strains gain access to the systemic circulation. Serologic results did not correlate with direct detection results and did not identify individual endovascular infection. CONCLUSIONS A significant proportion of atherosclerotic coronary arteries harbor viable C. pneumoniae. This finding supports the hypothesis of a chlamydial contribution to atherogenesis. Whether chlamydiae initiate atherosclerotic injury, facilitate its progression or colonize atheromata is unknown. However, the endovascular presence of viable bacteria justifies a controlled clinical investigation of antimicrobial treatment benefit in the therapy and prevention of CAD.

Preoperative Cerebral Oxygen Saturation and Clinical Outcomes in Cardiac Surgery

Background: The current study was designed to determine the relation between preoperative cerebral oxygen saturation (Sco2), variables of cardiopulmonary function, mortality, and morbidity in a heterogeneous cohort of cardiac surgery patients. Methods: In this study, 1,178 consecutive patients scheduled for on-pump surgery were prospectively studied. Preoperative Sco2, demographics, N-terminal pro-B-type natriuretic peptide, high-sensitive troponin T, clinical outcomes, and 30-day and 1-yr mortality were recorded. Results: Median additive EuroSCORE was 5 (range: 0–19). Thirty-day and 1-yr mortality and major morbidity (at least two major complications and/or a high-dependency unit stay of at least 10 days) were 3.5%, 7.7%, and 13.3%, respectively. Median minimal preoperative oxygen supplemented Sco2 (Sco2min-ox) was 64% (range: 15–92%). Sco2min-ox was correlated (all: P value <0.0001) with N-terminal pro-B-type natriuretic peptide (&rgr;: −0.35), high-sensitive troponin T (&rgr;: −0.28), hematocrit (&rgr;: 0.34), glomerular filtration rate (&rgr;: 0.19), EuroSCORE (&tgr;: 0.20), and left ventricular ejection fraction class (&tgr;: 0.12). Thirty-day nonsurvivors had a lower Sco2min-ox than survivors (median 58% [95% CI, 50.7–62%] vs. 64% [95% CI, 64–65%]; P < 0.0001). Receiver-operating curve analysis of Sco2min-ox and 30-day mortality revealed an area-under-the-curve of 0.71 (95% CI, 0.68–0.73%; P < 0.0001) in the total cohort and an area-under-the-curve of 0.77 (95% CI, 0.69–0.86%; P < 0.0001) in patients with a EuroSCORE more than 10. Logistic regression based on different EuroSCORE categories (0–2; 3–5, 6–10, >10), Sco2min-ox, and duration of cardiopulmonary bypass showed that a Sco2min-ox equal or less than 50% is an independent risk factor for 30-day and 1-yr mortality. Conclusions: Preoperative Sco2 levels are reflective of the severity of cardiopulmonary dysfunction, associated with short- and long-term mortality and morbidity, and may add to preoperative risk stratification in patients undergoing cardiac surgery.

Local Generation of C-Reactive Protein in Diseased Coronary Artery Venous Bypass Grafts and Normal Vascular Tissue

Background—Venous coronary artery bypass grafts (CABGs) are prone to accelerated atherosclerosis. In atherosclerotic diseases, serum C-reactive protein (CRP) levels have become an important diagnostic and prognostic marker. The origin of CRP in this setting remains to be elucidated. Methods and Results—Monoclonal anti-CRP identified CRP expression in medial and intimal &agr;-actin–positive smooth muscle cells (SMCs) of diseased CABGs with type V and VI lesions and also of native saphenous veins of atherosclerotic individuals. In addition, patent coronary arteries with type IV and V but not with type I through III lesions exhibited intense SMC staining for CRP. Calcified desobliterates of occluded coronary arteries with end-stage disease did not show SMC staining for CRP and were consistently negative for CRP mRNA, as detected by means of real-time polymerase chain reaction. However, CRP mRNA was expressed in 11 of 15 diseased CABGs and also in 10 of 15 native veins. By contrast, only 3 of 18 internal mammary and 4 of 12 radial arteries with virtually no atherosclerosis were positive for CRP mRNA. Conclusions—CRP is produced by SMCs of atherosclerotic lesions with active disease but not in end-stage plaques. The role of CRP constitutively expressed by normal vascular tissue in vein graft disease has yet to be elucidated.

Heart valve macro- and microstructure

Each heart valve is composed of different structures of which each one has its own histological profile. Although the aortic and the pulmonary valves as well as the mitral and the tricuspid valves show similarities in their architecture, they are individually designed to ensure optimal function with regard to their role in the cardiac cycle. In this article, we systematically describe the structural elements of the four heart valves by different anatomical, light- and electron-microscopic techniques that have been presented. Without the demand of completeness, we describe main structural features that are in our opinion of importance in understanding heart valve performance. These features will also have important implications in the treatment of heart valve disease. They will increase the knowledge in the design of valve substitutes or partial substitutes and may participate to improve reconstructive techniques. In addition, understanding heart valve macro- and microstructure may also be of benefit in heart valve engineering techniques.

A Comprehensive Evaluation of Rhythm Monitoring Strategies for the Detection of Atrial Fibrillation Recurrence: Insights from 647 Continuously Monitored Patients and Implications for Monitoring After Therapeutic Interventions

Background— Intermittent rhythm monitoring (IRM) to detect atrial fibrillation (AF) recurrence is employed to evaluate the success of therapeutic interventions. In a large population of patients with continuous monitoring (CM), we investigated the sensitivity of various frequencies and durations of IRM strategies on the detection of AF recurrence, the dynamics behind AF recurrence detection, and we describe measures to evaluate temporal AF recurrence. Methods and Results— Rhythm histories of 647 patients (mean AF burden, 0.12±0.22; median, 0.014; 687 patient-years) with implantable CM devices were reconstructed and analyzed. With the use of computationally intensive simulation, the sensitivity of IRM of various frequencies and durations on the identification of AF recurrence was evaluated. Prolonged-duration IRM was superior to shorter IRM (P<0.0001). However, even with aggressive IRM strategies, AF recurrence was not detected in a great proportion of patients. The temporal AF burden aggregation (AF density) was directly related to IRM sensitivity (P<0.0001). Even at similar AF burdens, patients with high-density AF required higher-frequency or prolonged-duration IRM to achieve the same sensitivity as in low-density AF (P<0.0001). Patients with high-density, low-burden AF benefit the most from CM for detection of AF recurrence. Conclusions— IRM follow-up is significantly inferior to CM. IRM strategies will not identify AF recurrence in a great proportion of patients at risk. Temporal AF characteristics play a significant role in AF recurrence detection with the use of IRM. For the scientific, evidence-based evaluation of AF treatments, CM should be strongly recommended. Prospective studies are required to evaluate whether CM to guide clinical management can also improve patient outcomes. Clinical Trial Registration— URL: http://www.clinicaltrials.gov. Unique identifier: NCT00806689.

Survival Comparison of the Ross Procedure and Mechanical Valve Replacement With Optimal Self-Management Anticoagulation Therapy Propensity-Matched Cohort Study

Background— It is suggested that in young adults the Ross procedure results in better late patient survival compared with mechanical prosthesis implantation. We performed a propensity score-matched study that assessed late survival in young adult patients after a Ross procedure versus that after mechanical aortic valve replacement with optimal self-management anticoagulation therapy. Methods and Results— We selected 918 Ross patients and 406 mechanical valve patients 18 to 60 years of age without dissection, aneurysm, or mitral valve replacement who survived an elective procedure (1994 to 2008). With the use of propensity score matching, late survival was compared between the 2 groups. Two hundred fifty-three patients with a mechanical valve (mean follow-up, 6.3 years) could be propensity matched to a Ross patient (mean follow-up, 5.1 years). Mean age of the matched cohort was 47.3 years in the Ross procedure group and 48.0 years in the mechanical valve group (P=0.17); the ratio of male to female patients was 3.2 in the Ross procedure group and 2.7 in the mechanical valve group (P=0.46). Linearized all-cause mortality rate was 0.53% per patient-year in the Ross procedure group compared with 0.30% per patient-year in the mechanical valve group (matched hazard ratio, 1.86; 95% confidence interval, 0.58 to 5.91; P=0.32). Late survival was comparable to that of the general German population. Conclusions— In comparable patients, there is no late survival difference in the first postoperative decade between the Ross procedure and mechanical aortic valve implantation with optimal anticoagulation self-management. Survival in these selected young adult patients closely resembles that of the general population, possibly as a result of highly specialized anticoagulation self-management, better timing of surgery, and improved patient selection in recent years.

Detection of Chlamydia pneumoniae But Not Cytomegalovirus in Occluded Saphenous Vein Coronary Artery Bypass Grafts

BACKGROUND A causal relation between atherosclerosis and chronic infection with Chlamydia pneumoniae and/or cytomegalovirus (CMV) has been suggested. Whether the unresolved problem of venous coronary artery bypass graft occlusion is related to infection with C pneumoniae and/or CMV has not been addressed. METHODS AND RESULTS Thirty-eight occluded coronary artery vein grafts and 20 native saphenous veins were examined. Detection of C pneumoniae DNA was performed by use of nested polymerase chain reaction (PCR). Homogenisates from the specimen were cultured for identification of viable C pneumoniae. Both conventional PCR and quantitative PCR for detection of CMV DNA were applied. Differential pathological changes (degree of inflammation, smooth muscle cell proliferation [MIB-1]) were determined and correlated to the detection of both microorganisms. C pneumoniae DNA could be detected in 25% of occluded vein grafts. Viable C pneumoniae was recovered from 16% of occluded vein grafts. Except for 1 native saphenous vein, all control vessels were negative for both C pneumoniae detection and culture. All pathological and control specimens were negative for CMV DNA detection. Pathological changes did not correlate with C pneumoniae detection. CONCLUSIONS Occluded aorto-coronary venous grafts harbor C pneumoniae but not CMV. The detection of C pneumoniae in occluded vein grafts warrants further investigation.

Management of porcelain aorta during coronary artery bypass grafting

BACKGROUND Patients with porcelain aorta carry a high risk of systemic embolism during coronary artery bypass grafting. No currently proposed surgical approach avoids manipulation of the heavily calcified ascending aorta. A novel surgical approach avoiding manipulation of the porcelain aorta was evaluated with regard to its efficacy in prevention of atheroemboli. METHODS The following surgical protocol was performed in 23 patients with porcelain aorta: (1) arterial cannulation of the axillary artery, (2) hypothermic fibrillatory arrest for performance of the distal anastomosis, and (3) construction of the proximal anastomosis to the inominate artery or to a disease-free area of the ascending aorta during hypothermic circulatory arrest. RESULTS The postoperative course was uneventful in all patients. No patient experienced a cerebrovascular accident or visceral organ injury as a result of atheroemboli. CONCLUSIONS The proposed surgical approach is safe and reliable in patients with porcelain aorta and has the potential to reduce the prevalence of stroke and systemic embolization associated with coronary artery bypass grafting in patients with porcelain aorta.

Valve-sparing aortic root replacement (remodeling/reimplantation) in acute type A dissection

BACKGROUND High reoperation rates after supracommissural tube graft replacement for acute type A dissection due to sinus of Valsalva dilation have been reported. Valve-sparing operations focusing on the replacement of the sinus of Valsalva are an appealing alternative. The applicability of these techniques in acute type A dissection remains debatable and results are limited. METHODS From 1992 to 1998, 20 patients with acute type A dissection received a valve-sparing aortic root replacement. Two different types of aortic valve-sparing operations were performed: the remodeling technique in 11 patients and the reimplantation technique in 9 patients. Patients were followed for 26 +/- 18 months. Echocardiographic studies were performed every 6 months. RESULTS There were 2 early postoperative deaths and no late death, no reoperation, and no thromboembolic events. The latest echocardiographic studies of the 18 survivors showed a competent valve in 12 and a trivial aortic valve insufficiency in 6 patients. The mean aortic valve pressure gradient was 4.3 +/- 1.3 mm Hg. CONCLUSIONS These midterm results support the surgical strategy of valve-sparing aortic root replacement in patients with acute type A dissection.

Quality of life in aortic valve replacement: pulmonary autografts versus mechanical prostheses

OBJECTIVES We sought to determine whether the quality of life (QoL) is different in patients after aortic valve replacement with mechanical prostheses or pulmonary autografts. BACKGROUND Quality of life after mechanical valve replacement may be affected by the risk of thromboembolism and anticoagulation, and after autograft implantation, by the risk of degeneration and re-operation especially of the homograft. METHODS Two groups of 40 patients each--one after the autograft procedure (group I) and one after mechanical valve implantation (group II)--were matched for age, gender and length of follow-up. At latest follow-up, all patients underwent routine echocardiography, the short-form health survey (SF-36) QoL survey and an extensive psychological investigation. RESULTS Patients with an autograft showed better QoL scales, as compared with mechanical valve recipients. The difference was significant for both the physical (72.72+/-20.00 vs. 60.27+/-26.07, p = 0.021) and psychological health sum scores (74.71+/-21.03 vs. 64.71+/-23.49, p = 0.046) and for the subtests of physical functioning (73.72+/-22.44 vs. 62.77+/-25.42, p = 0.049), physical pain (88.39+/-19.13 vs. 73.36+/-27.08, p < or = 0.006), general health perception (64.37+/-17.88 vs. 51.86+/-22.86, p < or = 0.008) and health change (61.89+/-18.94 vs. 50.11+/-24.37, p = 0.02). The QoL variables did not correlate to pressure gradients, ejection fraction and New York Heart Association functional class. Psychometric tests revealed no meaningful differences between the groups. CONCLUSIONS This study provides some evidence that patients with pulmonary autografts have greater benefit in terms of QoL, as compared with recipients of mechanical valve substitutes.