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Biomedical subjects

Nicolas Doll

Publications and source records attributed to Nicolas Doll.

At least 19 recordsLinked to original sources
PubMed2006

Rapid detection and successful treatment of esophageal perforation after radiofrequency ablation of atrial fibrillation: lessons from five cases.

INTRODUCTION: The aim of the study was to identify criteria for rapid recognition and successful treatment of esophageal perforation after radiofrequency ablation for atrial fibrillation (AF). METHODS AND RESULTS: Esophageal perforation occurred in five patients after intraoperative (n = 4) or percutaneous (n = 1) AF ablation. Patients presented with high fever (n = 3) or severe chest/epigastric pain (n = 2) 8-28 days after ablation. WBC count was elevated at presentation in all patients (15,460 +/- 2,910/muL), CRP showed a delayed rise. Thoracic CT detected free air in all. Neurologic complications occurred in three cases (60%) with a delay of 5-40 hours after first symptoms. Only one (20%) developed neurologic complications within the first 24 hours. Two patients (40%) died before surgery could be performed. In both, time from symptom onset to diagnosis was significant (24 and 36 hours). Three patients (60%) underwent esophageal resection and survived. In two of them, treatment was rapid with time from symptoms to surgery of 24 hours; they had favorable outcome. In the third surviving patient, surgery was late (5 days after first symptoms); permanent neurologic residues remained. CONCLUSION: The leading symptom of esophageal perforation is high fever or severe chest/epigastric pain. Fever is not necessarily present. Leukocytosis is the earliest and most sensitive laboratory marker, thoracic CT the most valuable diagnostic examination. The dramatic neurologic complications occur with a delay of at least a few hours after first symptoms. Immediate surgery may prevent neurologic complications and could possibly result in a high survival rate without residues. Delay of treatment seems to have devastating results.

Adult↗
PubMed2006

Emergency coronary artery bypass graft surgery for acute coronary syndrome: beating heart versus conventional cardioplegic cardiac arrest strategies.

BACKGROUND: Aim of this study was to compare the outcome of beating heart versus conventional coronary artery bypass graft (CABG) strategies in acute coronary syndromes for emergency indications. METHODS AND RESULTS: 638 consecutive patients with acute coronary syndrome (ACS) receiving emergency CABG surgery via midline sternotomy from January 2000 to September 2005 were evaluated. Propensity score analysis was used to predict the probability of undergoing beating heart (BH) (n=240) versus cardioplegic cardiac arrest (CA) (n=398) strategies. Patients presented with stable hemodynamics (n=531) or in cardiogenic shock (CS) (n=107). Hospital and follow-up outcome was compared by propensity score adjusted multiregression analysis. BH included 116 on-pump and 124 off-pump (OPCAB) procedures. There was a propensity to operate CS patients on the beating heart (multivariate odds ratio [OR], 3.8; P=0.001). Under stable hemodynamics significant predictors for BH selection were logEuroSCORE >20% (OR, 2.05), creatinine >1.8 mg/dL (OR, 4.12), complicated percutaneous coronary intervention (OR, 1.88), ejection fraction <30% (OR, 2.64), whereas left main disease (OR, 0.68), circumflex artery (OR, 0.32), and 3-vessel disease (OR, 0.67) indicated preference for cardioplegic arrest. Time from skin incision to culprit lesion revascularization was significantly reduced in BH patients. BH surgery led to a significant benefit in terms of less drainage loss, less transfusion requirement, less inotropic support, shorter ventilation time, lower stroke rate, and shorter intensive care unit stay. In CS, BH was associated with lower incidence of stroke, inotropic support, acute renal failure, new atrial fibrillation and sternal wound healing complications. In CS patients, hospital mortality rate was reduced when using beating heart strategies (P=0.048). Overall survival, major adverse cerebral and cardiovascular event rate, and repeated revascularization was comparable during a 5-year follow-up. CONCLUSIONS: Beating heart strategies are associated with an improved hospital outcome and comparable long-term results for high-risk patients presenting acute coronary syndrome with or without CS.

Adult↗
PubMed2006

Epicardial beating heart "off-pump" ablation of atrial fibrillation in non-mitral valve patients using new irrigated bipolar radiofrequency technology.

PURPOSE: We evaluated the use of a novel irrigated bipolar radiofrequency system for the treatment of nonmitral paroxysmal atrial fibrillation. DESCRIPTION: Between December 2003 and July 2005, 24 patients with paroxysmal atrial fibrillation underwent nonmitral cardiac procedures (coronary artery bypass grafting, n = 14; aortic valve replacement, n = 6; aortic valve replacement and coronary artery bypass grafting, n = 3; Bentall procedure, n = 1). In 12 of 14 of the coronary artery bypass graft patients, the procedure was performed off pump. All patients additionally underwent pulmonary vein isolation using the Medtronic Cardioblate BP system (Medtronic, Minneapolis, MN). Acute conduction block was evaluated in 16 patients. EVALUATION: Patients were followed-up for 6 months. Major adverse events include 1 patient death and 1 patient requiring implantation of a pacemaker. At discharge 19 of 22 patients (86.3%) were in stable sinus rhythm. After 3 months, stable sinus rhythm was found in 15 of 21 patients (71%). After 6 months, 15 of 15 patients (100%) were in stable sinus rhythm. Complete conduction block was accomplished in 29 of 32 pulmonary vein pairs (91%) after a single radiofrequency ablation and in 31 of 32 pairs (97%) after a second application. CONCLUSIONS: Pulmonary vein isolation with the use of this irrigated bipolar radiofrequency device is feasible, safe, and gains high experimental and clinical efficacy, including use during off-pump surgery.

Aged↗
PubMed2006

Both T-786C and G894T polymorphism of endothelial nitric oxide synthase affect in-vitro endothelium-dependent relaxation of internal mammary artery rings from patients with coronary artery disease.

OBJECTIVES: Polymorphisms of endothelial nitric oxide synthase (eNOS) gene in the promoter (T-786C) and exon 7 (G894T) have been suggested to attenuate endothelial function. As it is unknown whether these polymorphisms, on top of classical risk factors, further deteriorate endothelium-dependent vasomotion, we aimed to elucidate the impact of both polymorphisms on the ex-vivo vasomotor function of left internal mammary artery rings from patients with coronary artery disease (CAD) undergoing coronary bypass surgery (CABG). METHODS: Mammary artery rings from 51 consecutive patients with CAD were obtained during elective CABG. Endothelium-dependent ring relaxation was measured in vitro in an organ chamber using acetylcholine (10 to 3 x 10 mol/l). Polymorphisms were determined by polymerase chain reaction restriction length polymorphism. RESULTS: Thirty-three per cent of patients were positive for the T-786C polymorphism, 25% for the G894T polymorphism, and 18% carried mutated alleles in both loci. Maximal acetylcholine-induced ring relaxation was 46.7+/-3.2% in T-786C, 59.6+/-4.2% in G894T, and 66.7+/-7.4% in T-786C/G894T compared with 94.9+/-2.0% in wild-type subjects (P<0.05 versus T-786C, G894T, T-786C/G894T). Patients positive for an eNOS polymorphism with more than three cardiovascular risk factors displayed a further attenuation of acetylcholine-mediated relaxation (45+/-6 %) compared with having up to three risk factors (59+/-3%, P<0.05). CONCLUSION: In patients with CAD, in-vitro assessed endothelium-dependent relaxation of mammary arteries was significantly impaired in those positive for the T-786C or the G894T eNOS polymorphism. These results suggest that the presence of either one of the eNOS polymorphisms deteriorated endothelium-dependent vasodilatory capacity of large conduit vessels on top of classical risk factors in patients with CAD.

Aged↗
PubMed2006

Reverse remodeling of cardiac collagen protein expression after surgical therapy for experimental aortic stenosis.

BACKGROUND AND AIM OF THE STUDY: Reversal of myocardial collagen gene expression was examined in parallel to left ventricular reverse remodeling after surgical correction of experimental aortic stenosis. METHODS: A standard growing sheep model (age at baseline 6-8 months) was used. Measurements were performed at baseline (point A) when inducing left ventricular hypertrophy (LVH) through supracoronary banding, at 8.3 +/- 1.0 months later at surgical correction (point B), and after another 10.1 +/- 2.0 months during final examinations (point C). Gene expression for collagen I and III was also studied. RESULTS: Left ventricular function was stable throughout the study. The left ventricular mass index (LVMI) was 82 +/- 21 g/m2 at point A, 150 +/- 33 g/m2 at B, and 78 +/- 18 g/m2 at C (p <0.01). Myocardial fiber diameter was 11.3 +/- 0.8, 15.9 +/- 1.2 and 11.4 +/- 1 microm at points A, B and C, respectively (p <0.01). Protein expression for collagen I was 0.71 +/- 0.2 (at A), 1.13 +/- 0.3 (at B) and 0.85 +/- 0.4 (at C) (p <0.01), while that for collagen III was 0.72 +/- 0.4 (at A), 1.26 +/- 0.8 (at B) and 0.83 +/- 0.3 (at C) (p <0.01). There was a significant correlation between changes in LVMI and myocardial collagen expression. CONCLUSION: Complete reverse remodeling with regression of LVH and myocardial collagen protein expression can be anticipated after surgical correction of experimental aortic stenosis.

Animals↗
PubMed2005

Pacemaker dependent patients with device infection--a modified approach.

A modified surgical concept for temporary cardiac pacing in pacemaker dependent patients requiring total removal of infected devices is presented. Proximal to the infected pocket a permanent bipolar pacing lead is placed transcutaneously into the ipsilateral subclavian or jugular vein. The lead is placed in the right ventricle and fixed into the skin using the suture sleeve. Pacing is established by connecting an external pacing generator. Subsequently the infected device can be removed completely. After wound dressing the externalized lead is connected to a permanent VVI-pacemaker allowing for prolonged temporary pacing.

Aged↗
PubMed2005

Anomalous origin of the right coronary artery from the pulmonary artery combined with aortic valve stenosis.

We report the case of a 41-year-old patient presenting with anomalous of origin of the right coronary artery from the pulmonary artery (ARCAPA) and severe aortic valve stenosis. Surgical correction was performed by partial (T-shaped) sternotomy. After replacing the bicuspid aortic valve, the right coronary artery ostium was directly reimplanted into the aortic root. The main pulmonary artery was reconstructed using an autologous pericardial patch. Postoperative recovery was uneventful. Four cases involving an association of the bicuspid aortic valve and ARCAPA have been reported in the literature. This potential relationship should be considered whenever diagnosing a bicuspid aortic valve.

Abnormalities, Multiple↗
PubMed2005

Intraoperative fracture of the right coronary artery: recognition and management.

We describe the recognition and management of two patients who developed intraoperative fracture of the right coronary artery (RCA). Both patients had a calcified RCA without a hemodynamically significant stenosis. Compression of the right atrioventricular groove during the surgical procedure resulted in fracture of the RCA, leading to ventricular arrhythmias and hemodynamic instability. Coronary bypass grafting without cardioplegic arrest was used for definitive diagnosis and treatment. Both patients made a rapid and uneventful recovery.

Aorta↗
PubMed2005

Facilitated minimally invasive left ventricular epicardial lead placement.

PURPOSE: Atrial-synchronized biventricular pacing is an effective treatment option in patients with heart failure and interventricular conduction delay. Owing to a failed transvenous implantation in some patients, the left ventricular (LV) lead has to be placed surgically, usually by an anterolateral thoracotomy. We used a novel malleable epicardial lead placement tool (Epicardial Lead Implant Tool, Model 10626; Medtronic, Minneapolis, MN) that facilitates lead placement on the posterior aspect of the LV through an anterolateral minithoracotomy. DESCRIPTION: The tool consists of a malleable steel shaft with distal gripping tongs for the epicardial lead. Proximally, a thumbwheel and an actuator button allow fixation and release of the lead on the myocardium. EVALUATION: We used this tool in 7 patients through an anterolateral minithoracotomy. All patients had a safe, successful, and rather short procedure. No scopes were required. CONCLUSIONS: Epicardial LV lead placement through an anterolateral minithoracotomy is facilitated by using the Lead Implant Tool. Lead placement is achieved by the malleable shaft design, which enables perpendicular implantation of the lead pad on the posterior LV surface with an anterolateral approach.

Defibrillators, Implantable↗
PubMed2005

Impact of off-pump coronary bypass grafting on the prevalence of adverse perioperative outcome in women undergoing coronary artery bypass grafting surgery.

BACKGROUND: Female gender has been associated with a high prevalence of perioperative morbidity and mortality in coronary artery bypass grafting surgery (CABG). We attempted to determine a potential benefit of off-pump CABG as compared with on-pump CABG (OPCAB) with regard to perioperative outcome in female patients. METHODS: Data were prospectively gathered on 2,182 consecutive female patients undergoing CABG either with or without cardiopulmonary bypass from 1996 to 2001. The associations between OPCAB surgery in addition with 22 further preoperative patient-related or treatment-related variables and 26 perioperative outcome variables were assessed with multivariable logistic regression analysis. RESULTS: One hundred fifty-two (7.0%) female patients underwent OPCAB surgery during the study period. Women undergoing OPCAB had higher ejection fractions and received fewer coronary artery bypass grafts than CABG patients. Surgery using OPCAB was associated with shorter hospital stays, less bleeding, less transfusion requirements, and lower mortality than CABG. Furthermore, OPCAB surgery was independently associated with a lower prevalence of high perioperative transfusion requirement, postoperative respiratory insufficiency, postoperative renal insufficiency, and dialysis. Prevalence of postoperative blood loss of at least 500 mL was significantly higher after OPCAB surgery. CONCLUSIONS: OPCAB in female patients undergoing coronary artery bypass surgery is safe and seems to be beneficial with regard to perioperative outcome as compared with conventional on-pump CABG. For that reason, off-pump surgery may be an effective method of lowering morbidity and mortality in these relatively high-risk patients.

Aged↗
PubMed2005

Ablation of atrial fibrillation and esophageal injury: effects of energy source and ablation technique.

OBJECTIVE: The aim of this study was the evaluation of histologic changes induced on the esophagus by surgical ablation therapy for atrial fibrillation. METHODS: Experiments were performed on 39 sheep. Circular lesions were created endocardially or epicardially in the left atrium and at the pulmonary veins by using different energy sources: cryoablation, microwave, laser, and unipolar or bipolar radiofrequency. Temperatures inside the esophagus were measured, and esophageal tissue was investigated macroscopically and histopathologically. RESULTS: Esophageal damage was seen histologically in 24 of 39 cases. The epithelium was intact in all cases. Unipolar radiofrequency induced the most intensive esophageal lesions in 4 of 6 cases. The affected areas were small (1.56-3.01 mm) but reached deep into the tissue. Endocardial cryoablation resulted in wider lesions (2.01-8.54 mm), which were intensive in only 2 of 6 cases. Epicardial cryoablation and bipolar radiofrequency induced wide (1.11-6.8 mm) but mainly mild alterations. Endocardial and epicardial microwave energy affected the esophagus in single cases, and lesions were small (0.97-2.81 mm). Only in 1 case did laser energy induce a moderate alteration (5.30 mm) of the esophageal wall. CONCLUSIONS: Esophageal alterations were found in numerous cases. However, marked lesions were especially induced by endocardial unipolar radiofrequency and cryoablation.

Animals↗
PubMed2004

Prospectively randomized evaluation of stented xenograft hemodynamic function in the aortic position.

BACKGROUND: Standard stented aortic xenograft valves have not yet been compared regarding their hemodynamic function using a stratified intraoperative randomization protocol. METHODS AND RESULTS: 100 patients were prospectively included after intraoperative metric sizing of the decalcified aortic annulus. They received Mosaic (M) or Perimount (P) aortic valve replacement. Patient age was 73+/-5 years, 51 were female, and New York Heart Association (NYHA) functional class was 2.8+/-0.5. The 21-mm annulus group consisted of 5 (M)/7 (P) patients, the 23-mm annulus group of 20 (M)/20 (P), the 25-mm annulus group of 18 (M)/19 (P), and the 27-mm annulus group of 4 (M)/7 (P) patients, respectively. Hemodynamic function was evaluated using transthoracic echocardiography before discharge and at follow-up (438+/-352 days). Surgery was uncomplicated in all patients. Labeled valve sizes were 0.93 (M) and 1.05 (P) mm smaller than the annulus diameters (p=NS). In-hospital mortality was 5%, all nonvalve-related. Transvalvular blood flow velocities and transvalvular pressure gradients were significantly lower in the 25 P versus the 25 M group at baseline and in the 23 P and 25 P groups at follow-up. There was a significant regression of left ventricular mass index in all patients at follow-up. However, left ventricular mass regression was more pronounced after P aortic valve replacement. CONCLUSIONS: Labeled sizes of prosthetic heart valves implanted are smaller than the true aortic annulus. Both standard aortic xenografts compared in this prospectively randomized trial provide a sufficient hemodynamic and functional outcome.

Aged↗
PubMed2004

Five-year results of 219 consecutive patients treated with extracorporeal membrane oxygenation for refractory postoperative cardiogenic shock.

BACKGROUND: Postcardiotomy cardiogenic shock occurs in approximately 1% of patients. We prospectively evaluated the early and long-term outcome as well as predictors of survival when using temporary extracorporeal membrane oxygenation (ECMO) support. METHODS: During 5 years 219 of 18150 patients (1.2%) undergoing cardiac surgery (coronary artery bypass grafting, n = 119; aortic valve replacement, n = 24; coronary artery bypass grafting and aortic valve replacement, n = 21; coronary artery bypass grafting and mitral valve replacement, n = 11; other procedures, n = 44) required temporary postoperative ECMO support. The ECMO implantation was performed through the femoral vessels or through the right atrium and ascending aorta. Additional intraaortic balloon counterpulsation was employed in 144 patients to improve coronary blood flow. RESULTS: Mean duration of ECMO support was 2.8 +/- 2.2 days. One hundred thirty-four patients (60%) were successfully weaned from ECMO. Of these, 52 patients (24%) were discharged from the hospital after 29.9 +/- 24 days. The main cause of death was myocardial failure. Five-year follow-up is 96% complete; 37 patients (74%) were alive with reasonable exercise capacity. CONCLUSIONS: Extracorporeal membrane oxygenation is an acceptable technique for short-term treatment of refractory postoperative low cardiac output. It can save the lives of a group of very high risk patients.

Aged↗
PubMed2004

On-pump versus off-pump coronary artery bypass grafting: impact on postoperative renal failure requiring renal replacement therapy.

BACKGROUND: Despite refinements in perioperative patient management postoperative renal failure requiring hemofiltration or dialysis is still a common complication after coronary artery bypass grafting associated with impaired patient outcome. METHODS: Prospective data on 9,631 patients receiving myocardial revascularization with (coronary artery bypass grafting [n = 8,870]) or without cardiopulmonary bypass (off-pump coronary artery bypass grafting [n = 761]) between April 1996 and August 2001 were evaluated by univariate and multivariate logistic regression analysis. RESULTS: Overall prevalence of postoperative continuous renal replacement therapy was 4.1% (coronary artery bypass grafting, 4.3%; off-pump coronary artery bypass grafting, 1.8%; p = 0.001). Thirty of 40 selected preoperative and intraoperative patient and treatment related variables had a high association with the requirement for postoperative renal replacement therapy; fifteen of these variables were independent predictors in the whole study population. Off-pump coronary artery bypass surgery was identified as having a significantly lower predictive value for postoperative continuous renal placement therapy. In the subgroup of patients undergoing off-pump coronary artery bypass grafting surgery, a second multivariate logistic regression model revealed preoperative cardiogenic shock, urgent operation, intraoperative low cardiac output, and high transfusion requirement as independent predictors for postoperative renal replacement therapy. CONCLUSIONS: Patients with preoperative nondialysis dependent renal insufficiency are at a high risk for further decline in renal function requiring postoperative continuous renal replacement therapy. Off-pump coronary artery bypass surgery is associated with a lower prevalence of postoperative renal replacement therapy after coronary artery bypass grafting.

Aged↗
PubMed2004

A new cryoprobe for intraoperative ablation of atrial fibrillation.

We describe the use of a new argon cryoprobe (SurgiFrost) for isolated endocardial surgical ablation. A right lateral minithoracotomy and femoro-femoral cardiopulmonary bypass were applied. The basic mechanism of cryoablation is to remove heat from the targeted arrhythmogenic tissue followed by electrical isolation. In this first case of isolated treatment of atrial fibrillation using the new flexible SurgiFrost cryocatheter, we were able to perform pulmonary vein isolation reaching temperatures as low as -144 degrees C. The patient was discharged in sinus rhythm. This new argon cryoprobe represents an encouraging technology for the isolated endocardial as well as concomitant treatment of atrial fibrillation.

Atrial Fibrillation↗
PubMed2004

Predictors of delirium after cardiac surgery delirium: effect of beating-heart (off-pump) surgery.

BACKGROUND: Despite improved outcomes after cardiac operations, postoperative delirium remains a common complication that is associated with increased morbidity and prolonged hospital stay. METHODS: Univariate and multivariate predictors of postoperative delirium were determined from prospectively gathered data on 16,184 patients undergoing cardiac operations with cardiopulmonary bypass (conventional, n = 14,342) and without cardiopulmonary bypass (beating-heart surgery, n = 1847) between April 1996 and August 2001. Delirium was defined as a transient mental syndrome of acute onset characterized by global impairment of cognitive functions, a reduced level of consciousness, attentional abnormalities, increased or decreased psychomotor activity, and a disordered sleep-wake cycle. RESULTS: The overall prevalence of postoperative delirium was 8.4%. Of 49 selected patient-related risk factors and treatment variables, 35 were highly associated with postoperative delirium by univariate analysis. Stepwise logistic regression revealed the following variables as independent predictors of delirium: history of cerebrovascular disease, peripheral vascular disease, atrial fibrillation, diabetes mellitus, left ventricular ejection fraction of 30% or less, preoperative cardiogenic shock, urgent operation, intraoperative hemofiltration, operation time of 3 hours or more, and a high perioperative transfusion requirement. Two variables were identified as having a significant protective effect against postoperative delirium: beating-heart surgery and younger patient age. CONCLUSIONS: Postoperative delirium is a common complication in cardiac operations. The increased use of beating-heart surgery without cardiopulmonary bypass may lead to a lower prevalence of this complication and thus improve patient outcomes.

Age Distribution↗
PubMed2003

Predictors of prolonged ICU stay after on-pump versus off-pump coronary artery bypass grafting.

OBJECTIVE: To define predictors for prolonged ICU stay in order to improve patient outcome and reduce costs. PATIENTS AND METHODS: Prospective data on 10,759 patients undergoing coronary artery bypass grafting with and without use of cardiopulmonary bypass (coronary artery bypass grafting, CABG; n =8,917; off-pump coronary artery bypass grafting, OPCAB; n =765; minimally invasive direct coronary artery bypass grafting, MIDCAB; n =1,077) between April 1996 and August 2001 were subjected to univariate and, consecutively, to multivariate logistic regression analysis. Prolonged ICU stay was defined as intensive care treatment for three postoperative days and longer. MEASUREMENTS AND RESULTS: Mean duration of ICU stay was 3.8+/-6.9 days; overall prevalence of prolonged ICU stay was 37.1%. The hospital mortality was 3.5% (ICU > or =3 days: 5.9%; ICU <3 days: 2.0%). Out of 39 selected pre- and intraoperative patient- and treatment-related variables, by univariate analysis, 32 variables having a high association with prolonged ICU stay were identified. Using a stepwise logistic regression model, 20 variables were shown to be independent predictors for prolonged ICU stay. Both OPCAB and MIDCAB surgery were identified as having a significantly lower association with prolonged ICU stay. CONCLUSION: As prolonged ICU stay is associated with poor patient outcome and increased costs it is of utmost importance to identify patients at a high risk for prolonged ICU stay. More frequent off-pump CABG may optimize patient outcome.

Aged↗