Ulrich Stierle

Aortic atherosclerotic plaques as a source of systemic embolism

OBJECTIVES Our study was designed to determined the significance of aortogenic embolism in an unselected autopsy collective. BACKGROUND Although embolism arising from atherosclerotic plaques in the aorta has been acknowledged, the role of aortic atheromatosis among other well known sources of embolism remains to be further clarified. METHODS We examined the proximal part of the arterial system with regard to the presence of atherosclerotic lesions as well as cardiac changes in 120 consecutive necropsy studies. Pathologic evidence of embolic events was recorded. Clinical and neuropathologic data were also surveyed in all patients. RESULTS Among atherosclerotic lesions, fibrous plaques (p < 0.05) and calcified (p < 0.0001) and ulcerated lesions (p < 0.0001) as well as thrombi (p < 0.005) were observed significantly more frequently in the aortic arch and in the descending aorta than in the ascending aorta, whereas fatty streaks were distributed uniformly. In 40 (33%) of the 120 patients, we found pathologic evidence of arterial embolization. Multiple logistic regression analysis revealed a significant correlation between embolism and complicated atherosclerotic plaques in the aortic arch (odds ratio [OR] 5.8, 95% confidence interval [CI] 1.1 to 31.7, p < 0.05), severe ipsilateral carotid artery disease (OR 3.1, 95% CI 3.1 to 45.3, p < 0.001) and atrial fibrillation (OR 3.5, 95% CI 1.1 to 9.9, p < 0.05). CONCLUSIONS Complicated atherosclerotic plaques in the aortic arch represent an independent risk factor for systemic embolism similar to atrial fibrillation and severe atherosclerosis of the carotid arteries.

Twenty-Four–Hour Holter Monitor Follow-Up Does Not Provide Accurate Heart Rhythm Status After Surgical Atrial Fibrillation Ablation Therapy: Up to 12 Months Experience With a Novel Permanently Implantable Heart Rhythm Monitor Device

Background— Twenty-four–hour Holter monitoring (24HM) is commonly used to assess cardiac rhythm after surgical therapy of atrial fibrillation (AF). However, this “snapshot” documentation leaves a considerable diagnostic window and only stores short-time cardiac rhythm episodes. To improve accuracy of rhythm surveillance after surgical ablation therapy and to compare continuous heart rhythm surveillance versus 24HM follow-up intraindividually, we evaluated a novel implantable continuous cardiac rhythm monitoring (IMD) device (Reveal XT 9525). Methods and Results— Forty-five cardiac surgical patients (male 37, mean age 69.7±9.2 years) with a mean preoperative AF duration of 38±45 m were treated with either left atrial epicardial high-intensity focus ultrasound ablation (n=33) or endocardial cryothermy (n=12) in case of concomitant mitral valve surgery. Rhythm control readings were derived simultaneously from 24HM and IMD at 3-month intervals with a total recording of 2021 hours for 24HM and 220 766 hours for IMD. Mean follow-up was 8.30±3.97 m (range 0 to 12 m). Mean postoperative AF burden (time period spent in AF) as indicated by IMD was 37±43%. Sinus rhythm was documented in 53 readings of 24HM, but in only 34 of these instances by the IMD in the time period before 24HM readings (64%, P<0.0001), reflecting a 24HM sensitivity of 0.60 and a negative predictive value of 0.64 for detecting AF recurrence. Conclusion— For “real-life” cardiac rhythm documentation, continuous heart rhythm surveillance instead of any conventional 24HM follow-up strategy is necessary. This is particularly important for further judgment of ablation techniques, devices as well as anticoagulation and antiarrhythmic therapy.

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.

Factors associated with the development of aortic valve regurgitation over time after two different techniques of valve-sparing aortic root surgery

OBJECTIVE Early results after aortic valve-sparing root reconstruction are excellent. Longer-term follow-up, especially with regard to aortic valve function, is required for further judgment of these techniques. METHODS Between July of 1993 and September of 2006, 108 consecutive patients (mean age 53.0 +/- 15.8 years) underwent the Yacoub operation (group Y) and 83 patients underwent the David operation (group D). Innovative multilevel hierarchic modeling methods were used to analyze aortic regurgitation over time. RESULTS In general, aortic regurgitation increased with time in both groups. Factors associated with the development of a significant increase in aortic regurgitation were Marfan syndrome, concomitant cusp intervention, and preoperative aortic anulus dimension. In Marfan syndrome, the initial aortic regurgitation was higher in group Y versus group D (0.56 aortic regurgitation vs 0.29 aortic regurgitation, P = .049), whereas the mean annual progression rate of aortic regurgitation was marginally higher in group Y (0.132 aortic regurgitation vs 0.075 aortic regurgitation, P = .1). Concomitant cusp intervention was associated with a significant aortic regurgitation increase in both groups (P < .0001). There was a trend that smaller preoperative aortic annulus diameters in group D and larger diameters in group Y were associated with increased aortic regurgitation over time. CONCLUSION In regard to aortic regurgitation grade over time, patients with Marfan syndrome and a large preoperative aortic annulus diameter were better treated with the reimplantation technique, whereas those with a smaller diameter were better treated with the remodeling technique. Concomitant free-edge plication of prolapsing cusps was disadvantageous in both groups. Considering these factors may serve to improve the aortic valve longevity after valve-sparing aortic root surgery.

A Critical Reappraisal of the Ross Operation Renaissance of the Subcoronary Implantation Technique

Background— The autograft procedure, an option in aortic valve replacement, has undergone technical evolution. A considerable debate about the most favorable surgical technique in the Ross operation is still ongoing. Originally described as a subcoronary implant, the full root replacement technique is now the most commonly used technique to perform the Ross principle. Methods and Results— Between June of 1994 and June of 2005, the original subcoronary autograft technique was performed in 347 patients. Preoperative, perioperative, and follow-up data were collected and analyzed. Mean patient age at implantation was 44±13 years (range 14 to 71 years; 273 male, 74 female). Bicuspid valve morphology was present in 67%. The underlying valve disease was aortic regurgitation in 111 patients, stenosis in 46 patients, combined lesion in 188 patients, and active endocarditis in 22 patients (in 2 patients without stenosis or regurgitation). Concomitant procedures were performed in 130 patients. Clinical and echocardiographic follow-up visits were obtained annually (mean follow up 3.9±2.7 years, 1324 patient-years; completeness of follow-up 99.4%). The in-hospital mortality rate was 0.6% (n =2), and the late mortality was 1.7% (n=6), with 5 noncardiac deaths (4 cancer, 1 multiorgan failure after noncardiac surgery) and 1 cardiac death (sudden death). At last follow-up, 94% of the surviving patients were in New York Heart Association class I. Ross procedure–related valvular reoperations were necessary in 9 patients: Three received autograft explants, 5 received homograft explants, and 1 received a combined auto- and homograft explant. At last follow-up visit, autograft/homograft regurgitation grade II was present in 5/10 patients and grade III in 4/0. Maximum/mean pressure gradients were 7.4±6.2/3.7±2.1 mm Hg across the autograft and 15.3±9.4/7.6±5.0 mm Hg across the right ventricular outflow tract, respectively. Aortic root dilatation was not observed. Freedom from any valve-related intervention was 95% at 8 years (95% confidence interval 91% to 99%). Conclusion— Midterm follow-up of autograft procedures according to the original Ross subcoronary approach proves excellent clinical and hemodynamic results, with no considerable reoperation rates. Revival of the original subcoronary Ross operation should be taken into account when considering the best way to install the Ross principle.

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.

Relation of left atrial appendage function to the duration and reversibility of nonvalvular atrial fibrillation

Transesophageal echocardiography provides a tool to assess the functional integrity of the LAA during AF. This is the first study to demonstrate an association between LAA mechanical function and the duration of AF, which can be defined before cardioversion is undertaken. A high level of LAA mechanical function during AF seems to indicate a potential reversibility of the arrhythmia, whereas a low level of LAA outflow velocities is associated with stasis and elevated thromboembolic risk.

Myocardial ischemia in generalized coronary artery–left ventricular microfistulae

Generalized (multiple) arterio-systemic fistulae are fistulae arising from all three major coronary arteries and drain into the left ventricle are rare and the clinical and hemodynamic sequelae are incompletely understood. This communication is based on the clinical and hemodynamic data of a series of patients (eight cases out of 7262 consecutive patients) incidentally identified at coronary angiography combined with data from cases previously reported in literature. The aim was to assess the role of generalized coronary artery fistulae as a non-atherosclerotic cause of myocardial ischemia by means of a coronary sinus lactate study. Coronary sinus lactate study demonstrated myocardial ischemia in 6/7 patients. Mean arterio-coronary venous lactate difference decreased from 0.31+/-0.18 mmol/l (lactate extraction ratio, LER, 29.4+/-13.9%) at rest to 0.04+/-0.13 mmol/l (LER -4.0+/-13.3%) at peak exercise. Five minutes after cessation of pacing, lactate difference increased to 0.22+/-0.21 mmol/l (LER -20.7+/- 13.2%). At peak pacing stress, 4/7 patients showed frank lactate production, and two patients presented with a reduced cardiac lactate extraction rate also indicating myocardial ischemia metabolically. In the present study, we demonstrated a possible role of a coronary steal mechanism due to microfistulae pathways in the pathogenesis of myocardial ischemia in patients with generalized coronary artery-left ventricular microfistulae.

Fourteen years' experience with 501 subcoronary Ross procedures: surgical details and results.

OBJECTIVE During the past decade the Ross procedure using the full root has become the predominant surgical technique. However, progressive autograft dilatation and eventual failure remain a concern. Here we report on the surgical techniques and results of the subcoronary technique over a 14-year period. METHODS A total of 501 patients (mean age, 44.9 ± 12.9 years; 117 female; 384 male) were operated on from June 1994 to December 2007. The follow-up database, with a completeness of 98.2%, was closed on December 2008, comprising of 2931 patient-years with a mean follow-up of 5.9 ± 3.6 years (range, 0.1-14.1 years). RESULTS Surgical details are presented. Early and late mortality were 0.4% (n = 2) and 4% (n = 20), respectively, valve-related mortality was 1.2% (n = 6), whereas the overall survival did not differ from that of the normal population. Neurologic events occurred in 22 patients, major bleeding in 9, autograft endocarditis in 8, and homograft endocarditis in 10. Freedom from autograft and homograft reoperation was 91.9% at 10 years. For the majority of patients, hemodynamics was excellent and no root dilatation was observed. CONCLUSIONS Midterm results after the original subcoronary Ross procedure are excellent, including normal survival and low risk of valve-related morbidity. Longer-term results are necessary for continuous judgment of the subcoronary technique.

Autograft Regurgitation and Aortic Root Dimensions After the Ross Procedure The German Ross Registry Experience

Background— Autograft regurgitation and root dilatation after the Ross procedure is of major concern. We reviewed data from the German Ross Registry to document the development of autograft regurgitation and root dilatation with time and also to compare 2 different techniques of autograft implantation. Methods and Results— Between 1990 and 2006 1014 patients (786 men, 228 women; mean age 41.2±15.3 years) underwent the Ross procedure using 2 different implantation techniques (subcoronary, n =521; root replacement, n =493). Clinical and serial echocardiographic follow up was performed preoperatively and thereafter annually (mean follow up 4.41±3.11 years, median 3.93 years, range 0 to 16.04 years; 5012 patient-years). For statistical analysis of serial echocardiograms, a hierarchical multilevel modeling technique was applied. Eight early and 28 late deaths were observed. Pulmonary autograft reoperations were required in 35 patients. Initial autograft regurgitation grade was 0.49 (root replacement 0.73, subcoronary 0.38) with an annual increase of grade 0.034 (root replacement 0.0259, subcoronary 0.0231). Annulus and sinus dimensions did not exhibit an essential increase over time in both techniques, whereas sinotubular junction diameter increased essentially by 0.5 mm per year in patients with root replacement. Patients with the subcoronary implantation technique showed nearly unchanged dimensions. Bicuspid aortic valve morphology did not have any consistent impact on root dimensions with time irrespective of the performed surgical technique. Conclusions— The present Ross series from the German Ross Registry showed favorable clinical and hemodynamic results. Development of autograft regurgitation for both techniques was small and the annual progression thereof is currently not substantial. Use of the subcoronary technique and aortic root interventions with stabilizing measures in root replacement patients seem to prevent autograft regurgitation and dilatation of the aortic root within the timeframe studied.