Jens T. Lund

Aneurysm of the ductus arteriosus. A review of the literature and the surgical implications.

One hundred and forty-four cases of aneurysms of the ductus arteriosus (DAA) have been reported in the literature of which 106 appeared spontaneously and 38 followed surgical treatment of a patent ductus arteriosus (PDA). Within the last few years there has been an increasing number of reported spontaneous DAA. However, the real incidence is presumably still underestimated. Aortography is a well established diagnostic method. In neonates, transthoracic echocardiography has shown convincing potential, whereas in older children and adults, transoesophageal echocardiography has yielded very promising results. Serious complications following spontaneous DAA are rupture, erosion, infection and thromboembolism. In infants younger than 2 months of age, the complication rate is 31%, in children between 2 months and 15 years, 66%, in adults, 47%. The rate of complications following postoperative DAA is even higher: 91% of the unoperated cases died due to rupture or infection. The operative mortality in children older than 2 months and adults is low. In the neonate group, 2 of 8 died during operation. The operative mortality in patients with postoperative DAA was 26%. Based on information from the literature, we suggest prompt surgical treatment of all spontaneous DAA in patients older than 2 months of age, and in all patients with postoperative DAA. In infants, a DAA should be closely followed with echocardiography, as spontaneous regression has been reported in this age group. If no regression is seen within a few days, it should be surgically corrected.

Three-year follow-up in a subset of high-risk patients randomly assigned to off-pump versus on-pump coronary artery bypass surgery: the Best Bypass Surgery Trial

Objective To evaluate off-pump versus on-pump coronary artery bypass grafting (CABG) in patients with three-vessel disease and a high-risk operative profile. Design A randomised clinical trial. Setting Rigshospitalet, University Hospital, Copenhagen, Denmark. Participants 341 patients with three-vessel disease and a EuroSCORE of 5 or greater. Main exclusion criteria were previous heart surgery, poor left ventricular function (ejection fraction <30%), or unstable preoperative condition. Intervention CABG performed with versus without cardiopulmonary bypass. Main outcome measure The primary outcome was a composite of major adverse cardiac and cerebrovascular events (MACCE) including all-cause mortality, acute myocardial infarction, cardiac arrest with successful resuscitation, low cardiac output syndrome/cardiogenic shock, stroke and coronary reintervention. Results MACCE occurred in 69 (40%) patients allocated to off-pump versus 54 (33%) patients allocated to on-pump CABG during the median 3.7 years of follow-up (HR 1.22; 95% CI 0.86 to 1.75; p=0.26). All-cause mortality was significantly increased in the off-pump group (24% vs 15%; HR 1.66, 95% CI 1.02 to 2.73; p=0.04), but cardiac-related death was not significantly different (10% vs 7%; HR 1.30, 95% CI 0.64 to 2.66; p=0.47). An insignificant trend towards a reduction in myocardial infarction after off-pump CABG was observed (7% vs 14%; HR 0.53, 95% CI: 0.27 to 1.04; p=0.06). Conclusions No significant difference in the primary outcome of MACCE was found between off-pump and on-pump CABG. However, mortality seemed higher after off-pump CABG. Trial registration http://clinicaltrials.gov/ number, NCT00120991.

The impact of cardiac surgery in native valve infective endocarditis: Can euroSCORE guide patient selection?

BACKGROUND Decision making regarding surgical intervention in native valve endocarditis (NVE) is often complex and surgery is withheld in a number of patients either because medical treatment is considered the best treatment or because the risk of operation is considered too high. The objective of this study was to investigate the outcome of surgical treatment and to validate the ability of euroSCORE to predict operative mortality in NVE patients. METHODS Prospective cohort study including 323 consecutive NVE patients. Patients were divided into 3 groups based on treatment strategy and indication/contraindication for surgery. The additive and logistic euroSCORE was calculated and the observed and predicted mortality was compared. RESULTS Cardiac surgery was associated with a good prognosis, in-hospital and after 12months, compared to conservative treatment. After adjustment for confounders surgery was associated with a survival benefit (hazard ratio (HR) 0.45, 95% CI: 0.27-0.76%; p=0.003). When propensity score was used in regression adjustment, cardiac surgery was still associated with a better outcome after 12months (HR 0.41, 95% CI: 0.25-0.68; p<0.001). Observed mortality for patients receiving surgical treatment was 11% compared to a mean logistic euroSCORE mortality of 16% (NS). The discriminating ability of euroSCORE was good, area under the ROC curve 0.74 (95% CI: 0.64-0.84; p<0.001) logistic model and 0.75 (95% CI: 0.65-0.86; p<0.001) additive model. CONCLUSIONS Cardiac surgery was associated with a good prognosis when indicated regardless of euroSCORE, and surgery should only be withheld after thorough consideration. EuroSCORE remains a valuable tool to identify high-risk IE patients when surgery is considered.

First report on intraoperative vector flow imaging of the heart among patients with healthy and diseased aortic valves

The vector velocity method Transverse Oscillation (TO) implemented on a conventional ultrasound (US) scanner (ProFocus, BK Medical, Herlev, Denmark) can provide real-time, angle-independent estimates of the cardiac blood flow. During cardiac surgery, epicardial US examination using TO was performed on (A) 3 patients with healthy aortic valve and (B) 3 patients with aortic valve stenosis. In group B, the systolic flow of the ascending aorta had higher velocities, was more aliased and chaotic. The jet narrowed to 44% of the lumen compared to 75% in group A and with a vector concentration, a measure of flow complexity, of 0.41 compared to 0.87 in group A. The two groups had similar secondary flow of the ascending aorta with an average rotation frequency of 4.8 Hz. Simultaneous measurements were obtained with spectral Doppler (SD) and a thermodilution technique (TD). The mean difference in peak systolic velocity compared to SD in group A was 22% and 45% in B, while the mean difference in volume flow compared to TD in group A was 30% and 32% in B. TO can potentially reveal new information of cardiac blood flow, and may become a valuable diagnostic tool in the evaluation of patients with cardiovascular diseases.

Intraoperative cardiac ultrasound examination using vector flow imaging.

Conventional ultrasound (US) methods for blood velocity estimation only provide one-dimensional and angle-dependent velocity estimates; thus, the complexity of cardiac flow has been difficult to measure. To circumvent these limitations, the Transverse Oscillation (TO) vector flow method has been proposed. The vector flow method implemented on a commercial scanner provided real-time, angle-independent estimates of cardiac blood flow. Epicardiac and epiaortic, intraoperative US examinations were performed on three patients with stenosed coronary arteries scheduled for bypass surgery. Repeating cyclic beat-to-beat flow patterns were seen in the ascending aorta and pulmonary artery of each patient, but these patterns varied between patients. Early systolic retrograde flow filling the aortic sinuses was seen in the ascending aorta as well as early systolic retrograde flow in the pulmonary artery. In diastole, stable vortices in aortic sinuses of the ascending aorta created central antegrade flow. A stable vortex in the right atrium was seen during the entire heart cycle. The measurements were compared with estimates obtained intraoperatively with conventional spectral Doppler US using a transesophageal and an epiaortic approach. Mean differences in peak systole velocity of 11% and 26% were observed when TO was compared with transesophageal echocardiography and epiaortic US, respectively. In one patient, the cardiac output derived from vector velocities was compared with pulmonary artery catheter thermodilution technique and showed a difference of 16%. Vector flow provides real-time, angle-independent vector velocities of cardiac blood flow. The technique can potentially reveal new information of cardiovascular physiology and give insight into blood flow dynamics.

Vector Flow Imaging Compared with Conventional Doppler Ultrasound and Thermodilution for Estimation of Blood Flow in the Ascending Aorta

Transverse oscillation (TO) is a real-time ultrasound vector flow method implemented on a commercial scanner. The TO setup was examined on a flowrig with constant and pulsatile flow. Subsequently, 25 patients undergoing cardiac bypass surgery were scanned intraoperatively with TO on the ascending aorta and compared to transesophageal echocardiography (TEE) and pulmonary artery catheter thermodilution (PACTD). On the flowrig, TO had a precision of 5.5%, 9.4% and 14.7%, a percentage error of 18.2%, 14.6% and 40.7%, and a mean bias of 0.4 cm/s, 36.8 ml/min and 32.4 ml/min for velocity and flow rate (constant and pulsatile) estimation. The correlation coefficients for all flowrig evaluations were 0.99 indicating systematic bias. After bias correction, the percentage error was reduced to 11.5%, 12.6% and 15.9% for velocity and flow rate (constant and pulsatile) estimation. In the in vivo setup, TO, TEE, and PACTD had a precision of 21.9%, 13.7%, and 12.0%. TO compared with TEE and PACTD had a mean bias of 12.6 cm/s and −0.08 l/min, and a percentage error of 23.4%, and 36.7%, respectively. The percentage error was reduced to 22.9% for the TEE comparison, but increased to 43.8% for the PACTD comparison, after correction for the systematic bias found in the flowrig. TO is a reliable and precise method for velocity and flow rate estimation on a flowrig. However, TO with the present setup, is not interchangeable with PACTD for cardiac volume flow estimation, but is a reliable and precise angle-independent ultrasound alternative for velocity estimation of cardiac flow.

Graft patency after off-pump versus on-pump coronary artery surgery in high-risk patients

Abstract Objective. To compare angiographic graft patency in high-risk patients randomly allocated to off-pump vs. on-pump coronary artery bypass grafting (CABG). Design. From a randomised, single-centre clinical trial including patients undergoing isolated first-time coronary bypass surgery a subgroup of patients were scheduled to 1-year coronary angiographic follow-up. Patients had 3-vessel disease and a EuroSCORE ≥5. We evaluated graft patency using a patency index (percentage of patent grafts out of the total number of grafts in each patient). Results. One-year angiography was performed in 34 patients undergoing off-pump surgery and 35 patients undergoing on-pump surgery. The mean number of distal anastomoses was 3.38±0.65 in the off-pump group versus 3.46±0.61 in the on-pump group (NS). The number of patients without graft failure was 22 in the off-pump group and 24 in the on-pump group (NS). The overall patency index was 85% in the off-pump group versus 87% in the on-pump group with a mean difference of –2.1%, 95% confidence interval –12.9 to 8.7 (NS). Conclusions. In patients with 3-vessel disease and a high-risk profile we found no statistically significant difference in graft patency between off-pump and on-pump CABG at 1-year coronary angiographic follow-up. Trial registration: ClinicalTrials.gov identifier: NCT00120991.

One-year results of total arterial revascularization vs. conventional coronary surgery: CARRPO trial

AIMS To investigate clinical and angiographic outcomes after coronary surgery using total arterial revascularization (TAR). METHODS AND RESULTS We randomized 331 patients with multivessel or isolated left main disease to TAR [internal thoracic (ITA) and radial arteries] vs. conventional revascularization (CR) using left ITA and vein grafts. The primary angiographic outcome was the patency index: number of patent grafts (<50% stenosed) divided by number of constructed grafts. One-year angiography was complete for 83% of patients. Mean patency index (+/-SD) was 87 +/- 22% in the TAR group and 88 +/- 18% in the conventional group (P = 0.52). In 72% of TAR patients and 67% of the conventional group, all grafts were patent (P = 0.45). Multiple imputation of missing angiographic data did not influence on results. Within 1 year, 37 (23%) TAR patients and 43 (25%) conventional group patients suffered cardiac events (HR 1.09, 95% CI 0.70-1.69, P = 0.70). One patient (0.6%) in the TAR group and two (1.2%) in the conventional group died (P = 1.00). CONCLUSION Within 1 year post-operatively, TAR seems at least as safe and effective as CR. Prolonged follow-up will reveal whether this is sustained or superior results of TAR can justify a more general use.

Complete arterial coronary revascularisation using radial artery conduit for double thoracic artery inlet flow: arterial sling operation

BACKGROUND Coronary artery bypass graft surgery with arterial revascularisation of all diseased coronary vessels is considered highly efficient because arterial grafts have an excellent long-term patency compared with venous grafts. However, problems to reach the infero-lateral wall with the in situ internal thoracic arteries usually require alternative techniques. We present the first results of a new surgical principle using a free radial artery segment to complete the arterial coronary revascularisation and concomitantly connect the internal thoracic arteries. METHODS In patients referred for coronary bypass surgery and three-vessel disease an end-to-end anastomosis of the right internal thoracic artery and the radial artery segment preceded cardiopulmonary bypass, during which side-to-side anastomoses of the radial artery segment were used to revascularise stenotic branches of the right coronary and circumflex arteries. The left internal thoracic artery was used for revascularisation of stenotic branches of the left anterior descending artery, and finally an end-to-side anastomosis of the radial artery segment to the left internal thoracic artery was performed. Coronary artery blood flow was measured in 41 patients with Doppler flow probe. RESULTS One hundred and ninety-two coronary anastomoses (an average of 4.2 per patient) were performed in 46 patients. We measured a mean total blood flow in the arterial sling graft of 104ml/min (range 35-221ml/min), compared with 69 and 68ml/min of the single inlet right and left internal thoracic arteries, respectively (P<0.01). Flow capacities of 104 and 120ml/min of the right and left internal thoracic arteries were measured during clamp of both the aorta and the contralateral internal thoracic artery. The mean crossclamp duration was 77min (range 51-113min). Postoperative angiography demonstrated patent graft anastomoses to all coronary arteries. There were no perioperative deaths or myocardial infarctions. One patient had a minor postoperative stroke. DISCUSSION Complete arterial revascularisation can be achieved by the arterial sling operation with an acceptable crossclamp time and a high early rate of graft patency. The double arterial inlet provides a 50% higher blood flow to the beating heart and two-fold increase in the flow reserve compared with a single inlet. Although further research including long-term follow-up of this new principle is required, the present findings seem promising and suggest that the arterial sling operation has a potential role for complete arterial coronary revascularisation.

Trauma to the heart and thoracic aorta: the Copenhagen experience

Injuries of the heart and thoracic aorta (traumatic aortic rupture, TAR) remain amongst the most challenging of all injuries seen in the field of trauma and cardiothoracic surgery. The aim herein was to present our experience of such lethal injuries treated at Denmarks busiest hospital. We found 11 patients with cardiac injuries and nine patients with TAR. Five patients with cardiac injuries presented in shock of which two died. Eight patients with TAR were operated on using bypass without paraplegia. The Danish experience of heart trauma is limited but with satisfactory results. We recommend left heart bypass to prevent paraplegia in TAR.