Quality improvement mechanisms to improve lymph node staging for lung cancer: Trends from a statewide database.

OBJECTIVE: Our statewide thoracic quality collaborative has implemented multiple quality improvement initiatives to improve lung cancer nodal staging. We subsequently implemented a value-based reimbursement initiative to further incentivize quality improvement. We compare the impact of these programs to steer future quality improvement initiatives. METHODS: Since 2016, our collaborative focused on improving lymph node staging for lung cancer by leveraging unblinded, hospital-level metrics and collaborative feedback. In 2021, a value-based reimbursement initiative was implemented with statewide yearly benchmark rates for (1) preoperative mediastinal staging for ≥T2N0 lung cancer, and (2) sampling ≥5 lymph node stations. Participating surgeons would receive additional reimbursement if either benchmark was met. We reviewed patients from January 2015 to March 2023 at the 21 participating hospitals to determine the differential effects on quality improvement. RESULTS: We analyzed 6228 patients. In 2015, 212 (39%) patients had ≥5 nodal stations sampled, and 99 (51%) patients had appropriate preoperative mediastinal staging. During 2016 to 2020, this increased to 2253 (62%) patients and 739 (56%) patients, respectively. After 2020, 1602 (77%) patients had ≥5 nodal stations sampled, and 403 (73%) patients had appropriate preoperative mediastinal staging. Interrupted time-series analysis demonstrated significant increases in adequate nodal sampling and mediastinal staging before value-based reimbursement. Afterward, preoperative mediastinal staging rates briefly dropped but significantly increased while nodal sampling did not change. CONCLUSIONS: Collaborative quality improvement made significant progress before value-based reimbursement, which reinforces the effectiveness of leveraging unblinded data to a collaborative group of thoracic surgeons. Value-based reimbursement may still play a role within a quality collaborative to maintain infrastructure and incentivize participation.

Evidence-based opioid prescribing guidelines after lung resection: a prospective, multicenter analysis.

Background: Opioid prescribing guidelines have significantly decreased overprescribing and post-discharge use after cardiac surgery; however, limited recommendations exist for general thoracic surgery patients, a similarly high-risk population. We examined opioid prescribing and patient-reported use to develop evidence-based, opioid prescribing guidelines after lung cancer resection. Methods: This prospective, statewide, quality improvement study was conducted between January 2020 to March 2021 and included patients undergoing surgical resection of a primary lung cancer across 11 institutions. Patient-reported outcomes at 1-month follow-up were linked with clinical data and Society of Thoracic Surgery (STS) database records to characterize prescribing patterns and post-discharge use. The primary outcome was quantity of opioid used after discharge; secondary outcomes included quantity of opioid prescribed at discharge and patient-reported pain scores. Opioid quantities are reported in number of 5-mg oxycodone tablets (mean ± standard deviation). Results: Of the 602 patients identified, 429 met inclusion criteria. Questionnaire response rate was 65.0%. At discharge, 83.4% of patients were provided a prescription for opioids of mean size 20.5±13.1 pills, while patients reported using 8.2±13.0 pills after discharge (P<0.001), including 43.7% who used none. Those not taking opioids on the calendar day prior to discharge (32.4%) used fewer pills (4.4±8.1 vs. 11.7±14.9, P<0.001). Refill rate was 21.5% for patients provided a prescription at discharge, while 12.5% of patients not prescribed opioids at discharge required a new prescription before follow-up. Pain scores were 2.4±2.5 for incision site and 3.0±2.8 for overall pain (scale 0-10). Conclusions: Patient-reported post-discharge opioid use, surgical approach, and in-hospital opioid use before discharge should be used to inform prescribing recommendations after lung resection.

The Relationship Between Hospital Stroke Center Designation and TVT Reported Stroke: The Michigan TAVR Experience.

BACKGROUND: The 30-day rate of stroke after transcatheter aortic valve replacement (TAVR) has been suggested as a hospital quality metric. Thirty-day stroke rates for nonsurgical, high, and moderate-risk TAVR trials were 3.4% to 6.1%, whereas those in the national Transcatheter Valve Therapy (TVT) Registry for the same patient population were much lower. Hospital comprehensive stroke center (CSC) is the highest designation for integrated acute stroke recognition, management, and care. OBJECTIVES: Using Michigan TVT data, we assessed whether in-hospital post-TAVR stroke rates varied between CSC and non-CSC institutions. METHODS: TVT data submitted from the 22 Michigan Transcatheter Aortic Valve Replacement Collaborative participating institutions between January 1, 2016, and June 30, 2019, were included (N = 6,231). Bayesian hierarchical regression models accounting for patient clinical characteristics and hospital clustering were fitted to assess the association between hospital CSC accreditation and in-hospital post-TAVR stroke. Adjusted ORs and 95% credible intervals were estimated. The University of Michigan Institutional Review Board has waived the need for the approval of studies based on the data collected by the Blue Cross Blue Shield of Michigan Cardiovascular Consortium registry. RESULTS: There were 3,882 (62.3%) patients at 9 CSC sites and 2,349 (37.7%) patients at 13 non-CSC sites. CSC sites had significantly higher rates of in-hospital post-TAVR stroke (CSC: 2.65% vs non-CSC: 1.15%; P < 0.001). After adjustment, patients who underwent TAVR at a CSC hospital had a significantly higher risk of in-hospital stroke (adjusted OR: 2.21; 95% CI: 1.03-4.62). However, CSC designation was not significantly associated with other important post-TAVR clinical outcomes including 30-day mortality. CONCLUSIONS: Reported Michigan Transcatheter Aortic Valve Replacement Collaborative TVT stroke rates were significantly higher at sites with Joint Hospital Commission stroke designation status; however, other reported important clinical outcomes did not differ significantly based on this designation. CSC designation is a possible factor in stroke rate detection differences between TAVR institutions and might be a factor in the observed differences in stroke rates between TAVR trials and those reported in TVT. In addition, these data suggest that comparison between hospitals based on post-TAVR stroke rates is potentially problematic.

Predictors of Discharge Home Without Opioids After Cardiac Surgery: A Multicenter Analysis.

BACKGROUND: Whether all patients will require an opioid prescription after cardiac surgery is unknown. We performed a multicenter analysis to identify patient predictors of not receiving an opioid prescription at the time of discharge home after cardiac surgery. METHODS: Opioid-naïve patients undergoing coronary artery bypass grafting and/or valve surgery through a sternotomy at 10 centers from January to December 2019 were identified retrospectively from a prospectively maintained data set. Opioid-naïve was defined as not taking opioids at the time of admission. The primary outcome was discharge without an opioid prescription. Mixed-effects logistic regression was performed to identify predictors of discharge without an opioid prescription, and postdischarge opioid prescribing was monitored to assess patient tolerance of discharge without an opioid prescription. RESULTS: Among 1924 eligible opioid-naïve patients, mean age was 64 ± 11 years, and 25% were women. In total, 28% of all patients were discharged without an opioid prescription. On multivariable analysis, older age, longer length of hospital stay, and undergoing surgery during the last 3 months of the study were independent predictors of discharge without an opioid prescription, whereas depression, non-Black and non-White race, and using more opioid pills on the day before discharge were independent predictors of receiving an opioid prescription. Among patients discharged without an opioid prescription, 1.8% (10 of 547) were subsequently prescribed an opioid. CONCLUSIONS: Discharging select patients without an opioid prescription after cardiac surgery appears well tolerated, with a low incidence of postdischarge opioid prescriptions. Increasing the number of patients discharged without an opioid prescription may be an area for quality improvement.

Establishment and Implementation of Evidence-Based Opioid Prescribing Guidelines in Cardiac Surgery.

BACKGROUND: Despite the risk of new persistent opioid use after cardiac surgery, postdischarge opioid use has not been quantified and evidence-based prescribing guidelines have not been established. METHODS: Opioid-naive patients undergoing primary cardiac surgery via median sternotomy between January and December 2019 at 10 hospitals participating in a statewide collaborative were selected. Clinical data were linked to patient-reported outcomes collected at 30-day follow-up. An opioid prescribing recommendation stratified by inpatient opioid use on the day before discharge (0, 1-3, or ≥4 pills) was implemented in July 2019. Interrupted time-series analyses were performed for prescription size and postdischarge opioid use before (January to June) and after (July to December) guideline implementation. RESULTS: Among 1495 patients (729 prerecommendation and 766 postrecommendation), median prescription size decreased from 20 pills to 12 pills after recommendation release (P < .001), while opioid use decreased from 3 pills to 0 pills (P < .001). Change in prescription size over time was +0.6 pill/month before and -0.8 pill/month after the recommendation (difference = -1.4 pills/month; P = .036). Change in patient use was +0.6 pill/month before and -0.4 pill/month after the recommendation (difference = -1.0 pills/month; P = .017). Pain levels during the first week after surgery and refills were unchanged. Patients using 0 pills before discharge (n = 710) were prescribed a median of 0 pills and used 0 pills, while those using 1 to 3 pills (n = 536) were prescribed 20 pills and used 7 pills, and those using greater than or equal to 4 pills (n = 249) were prescribed 32 pills and used 24 pills. CONCLUSIONS: An opioid prescribing recommendation was effective, and prescribing after cardiac surgery should be guided by inpatient use.

A Simple Porcine Model of Inducible Sustained Atrial Fibrillation.

The surgical management of atrial fibrillation (AF) is an evolving field with a history of testing various lesion sets and ablation technologies. Previous animal models of AF require a chronic intervention to make AF reliably inducible. Our objective was to create an acute, reliable, and reproducible porcine model of sustained AF. To accomplish this, 21 adult domestic pigs underwent median sternotomy. Methods to induce AF were then performed sequentially: manual stimulation, rapid pacing (200 beats per minute), and then rapid pacing of 8 beats with a cycle length of 300 milliseconds, followed by an extra stimulus at decreasing cycle lengths. If AF was not induced, burst pacing was performed at a cycle length of 90 milliseconds for 30 seconds. If AF was still not induced, intravenous neostigmine was administered, and the process was repeated. Atrial fibrillation was considered sustained after 1 minute. Attempts at AF induction were successful in 18 (86%) of 21. Atrial fibrillation was induced during manual stimulation in four (19%), during rapid pacing in five (24%), during burst pacing in five (24%), and after the administration of neostigmine in four (19%). Mean (SD) duration of AF was 3.6 (2.6) minutes. Of the 18, 14 (78%) reverted to sinus rhythm spontaneously and 4 (22%) required an antiarrhythmic. This technique of inducing AF can easily be used to evaluate new technologies and lesion sets without the need for creating a chronic animal model.

Efficacy of a novel bipolar radiofrequency ablation device on the beating heart for atrial fibrillation ablation: a long-term porcine study.

OBJECTIVE: Over recent years, a variety of energy sources have been used to replace the traditional incisions of the Cox maze procedure for the surgical treatment of atrial fibrillation. This study evaluated the safety and efficacy of a new bipolar radiofrequency ablation device for atrial ablation in a long-term porcine model. METHODS: Six pigs underwent a Cox maze IV procedure on a beating heart off cardiopulmonary bypass using the AtriCure Isolator II bipolar ablation device (AtriCure, Inc, Cincinnati, Ohio). In addition, 6 pigs underwent median sternotomy and pericardiotomy alone to serve as a control group. All animals were allowed to survive for 30 days. Each pig underwent induction of atrial fibrillation and was then humanely killed to remove the heart en bloc for histologic assessment. Magnetic resonance imaging scans were also obtained preoperatively and postoperatively to assess atrial and ventricular function, pulmonary vein anatomy, valve function, and coronary artery patency. RESULTS: All animals survived the operation. Electrical isolation of the left atrial appendage and the pulmonary veins was documented by pacing acutely and at 30 days in all animals. No animal that underwent the Cox maze IV procedure was able to be induced into atrial fibrillation at 30 days postoperatively, compared with all the sham animals. All 257 ablations examined were discrete, linear, and transmural, with a mean lesion width of 2.2 +/- 1.1 mm and a mean lesion depth of 5.3 +/- 3.0 mm. CONCLUSIONS: The AtriCure Isolator II device was able to create reliable long-term transmural lesions of the modified Cox maze procedure on a beating heart without cardiopulmonary bypass 100% of the time. There were no discernible effects on ventricular or valvular function.

Vagal denervation and reinnervation after ablation of ganglionated plexi.

OBJECTIVE: Surgical ablation of ganglionated plexi has been proposed to increase efficacy of surgery for atrial fibrillation. This experimental canine study examined electrophysiologic attenuation and recovery of atrial vagal effects after ganglionated plexi ablation alone or with standard surgical lesion sets for atrial fibrillation. METHODS: Dogs were divided into 3 groups: group 1 (n = 6) had focal ablation of the 4 major epicardial ganglionated plexi fat pads, group 2 (n = 6) had pulmonary vein isolation with ablation, and group 3 (n = 6) had posterior left atrial isolation with ablation. All fat pads were ablated. Sinus and atrioventricular interval changes during bilateral vagosympathetic trunk stimulation were examined before and both immediately and 4 weeks after ablation. Vagally induced effective refractory period changes and mean QRST area changes (index of local innervation) were examined in 5 atrial regions. RESULTS: Sinus and atrioventricular interval changes and heart rate variability decreased immediately after ablation, but only sinus interval changes were restored significantly after 4 weeks in all groups. Ablation-modified vagal effects on effective refractory period or QRST area changed heterogeneously in groups 1 and 2. In group 3, regional vagal effects were attenuated extensively postablation in both atria. Posterior left atrial isolation with ablation incrementally denervated the atria. In the long term, vagal stimulation increased QRST area changes relative to control values in all groups. Heart rate variability was also assessed. CONCLUSIONS: Ganglionated plexi ablation significantly reduced atrial vagal innervation. Restoration of vagal effects at 4 weeks suggests early atrial reinnervation.

The effects of the Cox maze procedure on atrial function.

OBJECTIVE: The effects of the Cox maze procedure on atrial function remain poorly defined. The purpose of this study was to investigate the effects of a modified Cox maze procedure on left and right atrial function in a porcine model. METHODS: After cardiac magnetic resonance imaging, 6 pigs underwent pericardiotomy (sham group), and 6 pigs underwent a modified Cox maze procedure (maze group) with bipolar radiofrequency ablation. The maze group had preablation and immediate postablation left and right atrial pressure-volume relations measured with conductance catheters. All pigs survived for 30 days. Magnetic resonance imaging was then repeated for both groups, and conductance catheter measurements were repeated for the right atrium in the maze group. RESULTS: Both groups had significantly higher left atrial volumes postoperatively. Magnetic resonance imaging-derived reservoir and booster pump functional parameters were reduced postoperatively for both groups, but there was no difference in these parameters between the groups. The maze group had significantly higher reduction in the medial and lateral left atrial wall contraction postoperatively. There was no change in immediate left atrial elastance or in the early and 30-day right atrial elastance after the Cox maze procedure. Although the initial left atrial stiffness increased after ablation, right atrial diastolic stiffness did not change initially or at 30 days. CONCLUSIONS: Performing a pericardiotomy alone had a significant effect on atrial function that can be quantified by means of magnetic resonance imaging. The effects of the Cox maze procedure on left atrial function could only be detected by analyzing segmental wall motion. Understanding the precise physiologic effects of the Cox maze procedure on atrial function will help in developing less-damaging lesion sets for the surgical treatment of atrial fibrillation.

Surgical ablation for atrial fibrillation: the efficacy of a novel bipolar pen device in the cardioplegically arrested and beating heart.

OBJECTIVE: The introduction of ablation technology has simplified surgical intervention for atrial fibrillation. However, most ablation devices cannot create focal transmural lesions on the beating heart and have difficulty ablating specific regions of the atria, such as the atrioventricular isthmus, coronary sinus, and ganglionated plexus. The purpose of this study was to examine the efficacy of a pen-type bipolar radiofrequency ablation device on both arrested and beating hearts. METHODS: Endocardial and epicardial atrial tissues in the free wall, left atrial roof, atrioventricular annuli, and coronary sinus were ablated for varying time intervals (2.5-15 seconds) in porcine cardioplegically arrested (n = 6) and beating (n = 9) hearts. The hearts were stained with 1% 2,3,5-triphenyl-tetrazolium chloride solution and sectioned to determine lesion depth and width. In 5 animals epicardial fat pads containing ganglionated plexus were stimulated and ablated. RESULTS: Lesion depth increased with ablation time similarly in both arrested and beating hearts. Transmurality was fully achieved in the thin atrial tissue (<4 mm) at 10 seconds in the beating and arrested hearts. The device had a maximal penetration depth of 6.1 mm. Epicardial ablation of the coronary sinus showed complete penetration through the left posterior atrium only in the arrested heart. Seven of 17 fat pads demonstrated a vagal response. All vagal responses were eliminated after ablation. CONCLUSION: The bipolar pen effectively ablated atrial tissue in both arrested and beating hearts. This device might allow the surgeon to ablate tissue in regions not accessible to other devices during atrial fibrillation surgery.

Isolating the entire posterior left atrium improves surgical outcomes after the Cox maze procedure.

OBJECTIVES: The importance of each ablation line in the Cox maze procedure for treatment of atrial fibrillation remains poorly defined. This study evaluated differences in surgical outcomes of the procedure performed either with a single connecting lesion between the right and left pulmonary vein isolations versus 2 connecting lesions (the box lesion), which isolated the entire posterior left atrium. METHODS: Data were collected prospectively on 137 patients who underwent the Cox maze procedure from April 2002 through September 2006. Before May 2004, the pulmonary veins were connected with a single bipolar radiofrequency ablation lesion (n = 56), whereas after this time, a box lesion was routinely performed (n = 81). The mean follow-up was 11.8 +/- 9.6 months. RESULTS: The incidence of early atrial tachyarrhythmia was significantly higher in the single connecting lesion group compared with that in the box lesion group (71% vs 37%, P < .001). The overall freedom from atrial fibrillation recurrence was significantly higher in the box lesion group at 1 (87% vs 69%, P = .015) and 3 (96% vs 85%, P = .028) months. The use of antiarrhythmic drugs was significantly lower in the box lesion group at 3 (35% vs 58%, P = .018) and 6 (15% vs 44%, P = .002) months. CONCLUSIONS: Isolating the entire posterior left atrium by creating a box lesion instead of a single connecting lesion between the pulmonary veins showed a significantly lower incidence of early atrial tachyarrhythmias, higher freedom from atrial fibrillation recurrence at 1 and 3 months, and lower use of antiarrhythmic drugs at 3 and 6 months. A complete box lesion should be included in all patients undergoing the Cox maze procedure.

Pulmonary vein isolation and the Cox maze procedure only partially denervate the atrium.

OBJECTIVES: The effects of ablation lines on myocardial innervation and response to autonomic stimuli are unclear. This study examined the effects of radiofrequency ablation on atrial autonomic innervation and compared pulmonary vein isolation and the biatrial Cox maze procedure. METHODS: In 12 acute canines right and left vagosympathetic trunks and right and left stellate ganglia were isolated. Each nerve was stimulated before bipolar ablation, after pulmonary vein isolation, and after the Cox maze procedure. Nadolol (n = 6) and atropine (n = 6) were administered to block sympathetic and parasympathetic responses, respectively. Changes in heart rate and atrioventricular interval were compared. Changes in QRST area relative to an isoelectric baseline (index of local innervation) were calculated. RESULTS: Sympathetic stimulation of each nerve and parasympathetic stimulation of the vagosympathetic trunks caused significant changes in heart rate and atrioventricular interval. After pulmonary vein isolation, the effect of 33% of the nerves on heart rate changes was eliminated. The Cox maze procedure eliminated right stellate sympathetic effects on heart rate. Fifty percent of the nerves caused heart rate changes after the Cox maze procedure. There was no significant effect of either lesion set on atrioventricular interval changes. Stimulation of 50% of nerves after pulmonary vein isolation produced local area changes significantly different from control area. After the Cox maze procedure, a different 50% of the nerves produced local changes different from those seen after pulmonary vein isolation. CONCLUSIONS: Surgical ablation procedures disrupted innervation, affecting heart rate but not atrioventricular interval. Autonomic innervation affecting the atria was changed by pulmonary vein isolation and additionally by the Cox maze procedure. Residual autonomic effects were present even after the complete Cox maze procedure.

Incidence of residual choledocholithiasis detected by intraoperative cholangiography at the time of laparoscopic cholecystectomy in patients having undergone preoperative ERCP.

INTRODUCTION: The purpose of this study is to determine the incidence of residual common bile duct (CBD) stones after preoperative ERCP for choledocholithiasis and to evaluate the utility of routine intraoperative cholangiography (IOC) during laparoscopic cholecystectomy (LC) in this patient population. METHODS: All patients who underwent preoperative ERCP and interval LC with IOC from 5/96 to 12/05 were reviewed under an Institutional Review Board (IRB)-approved protocol. Data collected included all radiologic imaging, laboratory values, clinical and pathologic diagnoses, and results of preoperative ERCP and LC with IOC. Standard statistical analyses were used with significance set at p < 0.05. RESULTS: A total of 227 patients (male:female 72:155, mean age 51.9 years) underwent preoperative ERCP for suspicion of choledocholithiasis. One hundred and eighteen patients were found to have CBD stones on preoperative ERCP, and of these, 22 had choledocholithiasis diagnosed on IOC during LC. However, two patients had residual stones on completion cholangiogram after ERCP and were considered to have retained stones. Therefore, 20 patients overall were diagnosed with either interval passage of stones into the CBD or a false-negative preoperative ERCP. In the 109 patients without CBD stones on preoperative ERCP, nine patients had CBD stones on IOC during LC, an 8.3% incidence of interval passage of stones or false-negative preoperative ERCP. In both groups, there was no correlation (p > 0.05) between an increased incidence of CBD stones on IOC and a longer time interval between ERCP and LC, performance of sphincterotomy, incidence of cystic duct stones, or pathologic diagnosis of cholelithiasis. CONCLUSIONS: The overall incidence of retained or newly passed CBD stones on IOC during LC after a preoperative ERCP is 12.9%. Although the natural history of residual CBD stones after preoperative ERCP is not known, the routine use of IOC should be considered in patients with CBD stones on preoperative ERCP undergoing an interval LC.

The effect of ablation technology on surgical outcomes after the Cox-maze procedure: a propensity analysis.

OBJECTIVES: Since its introduction in 1987, the Cox-maze procedure has been the gold standard for the surgical treatment of atrial fibrillation. At our institution, this procedure has evolved from the cut-and-sew technique (Cox-maze III procedure) to one using bipolar radiofrequency energy and cryoablation as ablative sources to replace most incisions (Cox-maze IV procedure). This study compared surgical outcomes of patients undergoing the Cox-maze III procedure versus those of patients undergoing the Cox-maze IV procedure by using propensity analysis. METHODS: From April 1992 through July 2005, 242 patients underwent the Cox-maze procedure for atrial fibrillation. Of these, 154 patients had the Cox-maze III procedure, and 88 had the Cox-maze IV procedure. Logistic regression analysis was used to identify covariates among 7 baseline patient variables. Using the significant regression coefficients, each patient's propensity score was calculated, allowing selectively matched subgroups of 58 patients each. Operative outcomes were analyzed for differences. Late follow-up was available for 112 (97%) patients. Freedom from atrial fibrillation recurrence and survival was calculated at 1 year by using Kaplan-Meier analysis. RESULTS: The Cox-maze III procedure had significantly longer crossclamp times. There was no significant difference in intensive care unit and hospital stay, 30-day mortality, permanent pacemaker placement, early atrial tachyarrhythmias, late stroke, and survival. Freedom from atrial fibrillation recurrence was greater than 90% in both groups at 1 year. CONCLUSIONS: The use of bipolar radiofrequency ablation has simplified the Cox-maze procedure, making it applicable to virtually all patients with atrial fibrillation undergoing concomitant cardiac surgery. The Cox-maze IV procedure produces similar surgical outcomes to the Cox-maze III procedure at 1 year of follow-up.

Surgical ablation devices for atrial fibrillation.

The introduction of ablation technology has revolutionized the surgical treatment of atrial fibrillation (AF). It has greatly simplified surgical approaches and has significantly increased the number of procedures being performed. Various energy sources have been used clinically, including cryoablation, radiofrequency, microwave, laser, and high-frequency ultrasound. The goal of these devices is to create conduction block to either block activation wavefronts or to isolate the triggers of AF. All present devices have been shown to have clinical efficacy in some patients. The devices each have their unique advantages and disadvantages. It is important that surgeons develop accurate dose-response curves for new devices in clinically relevant models on both the arrested and beating heart. This will allow the appropriate use of technology to facilitate AF surgery.

Wide variations in energy delivery using an impedance-controlled algorithm in bipolar radiofrequency ablation: evidence against fixed time ablation.

OBJECTIVE: : Bipolar radiofrequency ablation recently has been used to replace many of the incisions of the Cox-Maze procedure in the surgical treatment of atrial fibrillation. The unique aspect of this technology is that it uses an algorithm based on changes in tissue conductance to determine the energy required to achieve a transmural lesion instead of relying on predetermined time and/or temperature criteria to determine ablation duration, as with most other ablation technologies. The purpose of this study was to determine variations in the different parameters of ablation needed to create transmural lesions in human atria. METHODS: : Initial impedance, total energy, temperature, and ablation time were measured in 38 patients undergoing surgery, using an impedance-controlled bipolar radiofrequency device (AtriCure Isolator, Cincinnati, OH). Lesions were categorized into the following groups: right atrial free wall, left atrial free wall, atrium up to mitral valve annulus, atrium up to tricuspid valve annulus, and right or left pulmonary veins. RESULTS: : There was a wide range of initial impedance (32.3 to 760.7 Ohms), and this correlated with total energy delivered (r = -0.31, P = 0.002). Ablation times varied widely (2.0 to 29.9 seconds) and were longer on left atrial structures than right (P < 0.005) and shortest near the tricuspid annulus (P < 0.001). Mean tissue temperature 1 mm from the electrode was only 45.7 ± 7.8°C (range, 23.7°C to 69.3°C). CONCLUSIONS: : Bipolar ablation of different atrial structures required widely different amounts of energy and ablation times, probably as the result of the inhomogeneity of atrial geometry and tissue impedance. These data cast doubt on the efficacy of any fixed-time or temperature ablations in the clinical setting.

Combined off-pump coronary revascularization: ascending aorta to carotid bypass.

A 76-year-old man with symptomatic cerebral vascular disease and coronary artery disease was treated with simultaneous off-pump bypass and cerebral revascularization. With the emergence of off-pump coronary artery operation as a viable option for coronary revascularization we believe that this procedure will become our method of choice for combined cerebral and coronary artery disease.