A Modular Communicative Leadless Pacing-Defibrillator System

BACKGROUND

The subcutaneous implantable cardioverter-defibrillator (ICD) is associated with fewer lead-related complications than a transvenous ICD; however, the subcutaneous ICD cannot provide bradycardia and antitachycardia pacing. Whether a modular pacing-defibrillator system comprising a leadless pacemaker in wireless communication with a subcutaneous ICD to provide antitachycardia and bradycardia pacing is safe remains unknown.

METHODS

We conducted a multinational, single-group study that enrolled patients at risk for sudden death from ventricular arrhythmias and followed them for 6 months after implantation of a modular pacemaker-defibrillator system. The safety end point was freedom from leadless pacemaker-related major complications, evaluated against a performance goal of 86%. The two primary performance end points were successful communication between the pacemaker and the ICD (performance goal, 88%) and a pacing threshold of up to 2.0 V at a 0.4-msec pulse width (performance goal, 80%).

RESULTS

We enrolled 293 patients, 162 of whom were in the 6-month end-point cohort and 151 of whom completed the 6-month follow-up period. The mean age of the patients was 60 years, 16.7% were women, and the mean (±SD) left ventricular ejection fraction was 33.1±12.6%. The percentage of patients who were free from leadless pacemaker-related major complications was 97.5%, which exceeded the prespecified performance goal. Wireless-device communication was successful in 98.8% of communication tests, which exceeded the prespecified goal. Of 151 patients, 147 (97.4%) had pacing thresholds of 2.0 V or less, which exceeded the prespecified goal. The percentage of episodes of arrhythmia that were successfully terminated by antitachycardia pacing was 61.3%, and there were no episodes for which antitachycardia pacing was not delivered owing to communication failure. Of 162 patients, 8 died (4.9%); none of the deaths were deemed to be related to arrhythmias or the implantation procedure.

CONCLUSIONS

The leadless pacemaker in wireless communication with a subcutaneous ICD exceeded performance goals for freedom from major complications related to the leadless pacemaker, for communication between the leadless pacemaker and subcutaneous ICD, and for the percentage of patients with a pacing threshold up to 2.0 V at a 0.4-msec pulse width at 6 months. (Funded by Boston Scientific; MODULAR ATP ClinicalTrials.gov NCT04798768.).

Dual-energy lattice-tip ablation system for persistent atrial fibrillation: a randomized trial

Clinical outcomes of catheter ablation for atrial fibrillation (AF) are suboptimal due, in part, to challenges in achieving durable lesions. Although focal point-by-point ablation allows for the creation of any required lesion set, this strategy necessitates the generation of contiguous lesions without gaps. A large-tip catheter, capable of creating wide-footprint ablation lesions, may increase ablation effectiveness and efficiency. In a randomized, single-blind, non-inferiority trial, 420 patients with persistent AF underwent ablation using a large-tip catheter with dual pulsed field and radiofrequency energies versus ablation using a conventional radiofrequency ablation system. The primary composite effectiveness endpoint was evaluated through 1 year and included freedom from acute procedural failure and repeat ablation at any time, plus arrhythmia recurrence, drug initiation or escalation or cardioversion after a 3-month blanking period. The primary safety endpoint was freedom from a composite of serious procedure-related or device-related adverse events. The primary effectiveness endpoint was observed for 73.8% and 65.8% of patients in the investigational and control arms, respectively (P < 0.0001 for non-inferiority). Major procedural or device-related complications occurred in three patients in the investigational arm and in two patients in the control arm (P < 0.0001 for non-inferiority). In a secondary analysis, procedural times were shorter in the investigational arm as compared to the control arm (P < 0.0001). These results demonstrate non-inferior safety and effectiveness of the dual-energy catheter for the treatment of persistent AF. Future large-scale studies are needed to gather real-world evidence on the impact of the focal dual-energy lattice catheter on the broader population of patients with AF. ClinicalTrials.gov identifier: NCT05120193 .

Early real-world implant experience with a helix-fixation ventricular leadless pacemaker

BACKGROUND

Roughly one in six patients receiving conventional transvenous pacemaker systems experience significant complications within 1 year of implant, mainly due to the transvenous lead and subcutaneous pocket. A new helix-fixation single-chamber ventricular leadless pacemaker (LP) system capable of pre-deployment exploratory electrical mapping is commercially available. Such an LP may mitigate complications while streamlining the implantation. In this study, the initial real-world implant experience of the helix-fixation LP was evaluated following its commercial release.

METHODS

In patients indicated for single-chamber right ventricular pacing, helix-fixation Aveir VR LPs (Abbott, Abbott Park, IL) were implanted using the dedicated loading tool, introducer, and delivery catheter. Implant procedural characteristics, electrical parameters, and any 30-day procedure-related adverse events of consecutive implant attempts were retrospectively evaluated.

RESULTS

A total of 167 patients with Class I indication for permanent pacing received implants in four North American centers (57% male, 70 years old). Pre-fixation electrical mapping of potential sites allowed repositioning to be avoided in 95.7% of patients. Median [interquartile range] LP procedure and fluoroscopy durations were 25.5 min [20.0, 35.0] and 5.7 min [4.0, 9.2], respectively. Pacing capture threshold, sensed R-wave amplitude, and impedance were 0.8 V [0.5, 1.3], 9.0 mV [6.0, 12.0], and 705 Ω [550, 910], respectively. Implantation was successful in 98.8% of patients, with 98.2% free from acute adverse events.

CONCLUSIONS

The initial, real-world experience of the helix-fixation ventricular leadless pacemaker demonstrated safe and efficient implantation with minimal repositioning, viable electrical metrics, and limited acute complications.

Intracardiac vs Transesophageal Echocardiography for Left Atrial Appendage Occlusion With Watchman FLX in the U.S

BACKGROUND

Intraprocedural imaging is critical for device delivery in transcatheter left atrial appendage occlusion (LAAO). Although pivotal trials of LAAO devices were conducted using transesophageal echocardiography (TEE), intracardiac echocardiography (ICE) is an emerging imaging modality.

OBJECTIVES

This study compared outcomes after ICE- and TEE-guided Watchman FLX implantation in the SURPASS (SURveillance Post Approval AnalySiS Plan) nationwide LAAO registry.

METHODS

Baseline characteristics were compared using chi-square and t-tests. Outcomes were reported in unadjusted and adjusted comparisons via propensity weighting.

RESULTS

Between August 2020 and September 2021, LAAO was attempted in 39,759 patients at 698 sites, including 2,272 cases (5.7%) with ICE and 31,835 (80.0%) with TEE. ICE and TEE patients had similar baseline characteristics and mean procedural times (ICE 82 minutes vs TEE 78 minutes). ICE patients were less likely to receive general anesthesia (54% vs 98%, P < 0.01). Successful device implantation (98.3% vs 97.6%) and complete seal rates at 45 days were similar (n = 25,280; 83% vs 82%). Most adverse event rates were similar; unadjusted mortality rates at 45 days were 1.1% for ICE vs 0.8% for TEE (P = 0.14), and 1.0% vs 0.7% (P = 0.27) in adjusted analyses. Even after adjustment, pericardial effusion rates requiring intervention were significantly higher with ICE at 45 days (1.0% vs 0.5%; P = 0.02). This rate decreased as operators performed more ICE-guided procedures, although 82% of operators had performed <10 ICE-guided procedures overall.

CONCLUSIONS

In the largest comparison to date, ICE use was infrequent. ICE and TEE both achieved high rates of complete LAAO. ICE was associated with significantly higher rates of pericardial effusion requiring intervention.

DAPT Is Comparable to OAC Following LAAC With WATCHMAN FLX: A National Registry Analysis

BACKGROUND

Left atrial appendage occlusion (LAAO) is an approved alternative for stroke prevention in atrial fibrillation for patients with an "appropriate rationale" to avoid long-term oral anticoagulation (OAC). Many patients undergoing LAAO are at high risk of bleeding.

OBJECTIVES

This study sought to investigate whether dual antiplatelet therapy (DAPT) is a safe alternative to OAC (direct oral anticoagulation [DOAC] or warfarin) with aspirin after LAAO.

METHODS

Using National Cardiovascular Data Registry LAAO registry data, patients undergoing Watchman FLX (Boston Scientific) implantation (August 5, 2020-September 30, 2021) were included in 1:1 propensity-matched analyses comparing discharge medication regimens (DAPT, DOAC/aspirin, or warfarin/aspirin). A composite endpoint (death, stroke, major bleeding, and systemic embolism), its components, and device-related thrombus between discharge and 45 days were evaluated.

RESULTS

In 49,968 patients implanted with the Watchman FLX during the study period, the mean age was 77 years, and 40% were women. Postimplant DOAC/aspirin was prescribed in 24,497 patients, warfarin/aspirin in 3,913, and DAPT in 4,155. DAPT patients had more comorbid conditions than patients receiving OAC/aspirin. After propensity score matching, the 45-day composite endpoint rates were similar among the groups (DAPT = 3.44% vs DOAC/aspirin: 4.06%; P = 0.13 and DAPT = 3.23% vs warfarin/aspirin: 3.08%; P = 0.75). Death, stroke, and device-related thrombus were also similar; major bleeding was slightly increased in DOAC/aspirin patients (DAPT = 2.48% vs DOAC/aspirin = 3.25%; P = 0.04 and DAPT = 2.25% vs warfarin/aspirin = 2.22%; P = 0.93).

CONCLUSIONS

In a large registry, DAPT had a similar safety profile compared with current Food and Drug Administration-approved postimplant drug regimens of OAC with aspirin following LAAO with the Watchman FLX. Shared decision making for nonpharmacologic stroke prevention should include a discussion of postprocedure medical therapy options.

Retrieval of Chronically Implanted Dual-chamber Leadless Pacemakers in an Ovine Model

BACKGROUND

The clinical utilization of leadless pacemakers (LPs) as an alternative to traditional transvenous pacemakers is likely to increase with the advent of dual-chamber LP systems. Since device retrieval to allow LP upgrade or replacement will become an important capability, the first such dual-chamber, helix-fixation LP system (Aveir DR; Abbott, Abbott Park, IL) was specifically designed to allow catheter-based retrieval. In this study, the preclinical performance and safety of retrieving chronically implanted dual-chamber LPs was evaluated.

METHODS

Atrial and ventricular LPs were implanted in the right atrial appendage and right ventricular apex of 9 healthy ovine subjects. After ≈2 years, the LPs were retrieved using a dedicated transvenous retrieval catheter (Aveir Retrieval Catheter; Abbott) by snaring, docking, and unscrewing from the myocardium. Comprehensive necropsy/histopathology studies were conducted to evaluate device- and procedure-related outcomes.

RESULTS

At a median of 1.9 years postimplant (range, 1.8-2.6), all 18 of 18 (100%) LPs were retrieved from 9 ovine subjects without complications. The median retrieval procedure duration for both LPs, from first-catheter-in to last-catheter-out, was 13.3 minutes (range, 2.5-36.4). Postretrieval, all right atrial, and right ventricular implant sites demonstrated minimal tissue disruption, with intact fibrous tissue limited to the distal device body. No significant device-related trauma, perforation, pericardial effusion, right heart or tricuspid valve injury, or chronic pulmonary thromboembolism were observed at necropsy.

CONCLUSIONS

This preclinical study demonstrated the safe and effective retrieval of chronically implanted, helix-fixation, dual-chamber LP systems, paving the way for clinical studies of LP retrieval.

Rationale and design of a randomized study comparing the Watchman FLX device to DOACs in patients with atrial fibrillation

BACKGROUND

Percutaneous left atrial appendage (LAA) closure (LAAC) was developed as a nonpharmacologic alternative to oral anticoagulants (OACs) in patients with atrial fibrillation (AF) who are at an increased risk for stroke or systemic embolism. The Watchman device permanently seals off the LAA to prevent thrombi from escaping into the circulation. Previous randomized trials have established the safety and efficacy of LAAC compared to warfarin. However, direct OACs (DOACs) have become the preferred pharmacologic strategy for stroke prevention in patients with AF, and there is limited data comparing Watchman FLX to DOACs in a broad AF patient population. CHAMPION-AF is designed to prospectively determine whether LAAC with Watchman FLX is a reasonable first-line alternative to DOACs in patients with AF who are indicated for OAC therapy.

STUDY DESIGN

A total of 3,000 patients with a CHA2DS2-VASc score ≥2 (men) or ≥3 (women) were randomized to Watchman FLX or DOAC in a 1:1 allocation at 142 global clinical sites. Patients in the device arm were to be treated with DOAC and aspirin, DOAC alone, or DAPT for at least 3 months postimplant followed by aspirin or P2Y12 inhibitor for 1-year. Control patients were required to take an approved DOAC for the duration of the trial. Clinical follow-up visits are scheduled at 3- and 12-months, and then annually through 5 years; LAA imaging is required at 4 months in the device group. Two primary end points will be evaluated at 3 years: (1) composite of stroke (ischemic/hemorrhagic), cardiovascular death, and systemic embolism compared for noninferiority, and (2) nonprocedural bleeding (International Society on Thrombosis and Haemostasis [ISTH] major and clinically relevant nonmajor bleeding) tested for superiority in the device arm against DOACs. The third primary noninferiority end point is the composite of ischemic stroke and systemic embolism at 5 years. Secondary end points include 3- and 5-year rates of (1) ISTH-defined major bleeding and (2) the composite of cardiovascular death, all stroke, systemic embolism, and nonprocedural ISTH bleeding.

CONCLUSIONS

This study will prospectively evaluate whether LAAC with the Watchman FLX device is a reasonable alternative to DOACs in patients with AF.

CLINICAL TRIAL REGISTRATION

NCT04394546.

Two-Year Outcomes With a Next-Generation Left Atrial Appendage Device: Final Results of the PINNACLE FLX Trial

Background The PINNACLE FLX (Protection Against Embolism for Non-valvular AF [Atrial Fibrillation] Patients: Investigational Device Evaluation of the Watchman FLX LAA [Left Atrial Appendage] Closure Technology) trial evaluated the safety and efficacy of a next-generation left atrial appendage closure device (WATCHMAN FLX; Boston Scientific, Marlborough, MA). At 1 year, the study met the primary end points of safety and anatomical efficacy/appendage closure. This final report of the PINNACLE FLX trial includes the prespecified secondary end point of ischemic stroke or systemic embolism at 2 years, also making it the first report of 2-year outcomes with this next-generation left atrial appendage closure device. Methods and Results Patients with nonvalvular atrial fibrillation with CHA₂DS₂-VASc score ≥2 (men) or ≥3 (women), with an appropriate rationale for left atrial appendage closure, were enrolled to receive the left atrial appendage closure device at 29 US centers. Adverse events were assessed by an independent clinical events committee, and imaging was assessed by independent core laboratories. Among 395 implanted patients (36% women; mean age, 74 years; CHA₂DS₂-VASc, 4.2±1.5), the secondary efficacy end point of 2-year ischemic stroke or systemic embolism was met, with an absolute rate of 3.4% (annualized rate, 1.7%) and an upper 1-sided 95% confidence bound of 5.3%, which was superior to the 8.7% performance goal. Two-year rates of adverse events were as follows: 9.3% all-cause mortality, 5.5% cardiovascular death, 3.4% all stroke, and 10.1% major bleeding (Bleeding Academic Research Consortium 3 or 5). There were no additional systemic embolisms, device embolizations, pericardial effusions, or symptomatic device-related thrombi after 1 year. Conclusions The secondary end point of 2-year stroke or systemic embolism was met at 3.4%. In these final results of the PINNACLE FLX trial, the next-generation WATCHMAN FLX device demonstrated favorable safety and efficacy outcomes.

Advances in Cardiac Electrophysiology

Despite the global COVID-19 pandemic, during the past 2 years, there have been numerous advances in our understanding of arrhythmia mechanisms and diagnosis and in new therapies. We increased our understanding of risk factors and mechanisms of atrial arrhythmias, the prediction of atrial arrhythmias, response to treatment, and outcomes using machine learning and artificial intelligence. There have been new technologies and techniques for atrial fibrillation ablation, including pulsed field ablation. There have been new randomized trials in atrial fibrillation ablation, giving insight about rhythm control, and long-term outcomes. There have been advances in our understanding of treatment of inherited disorders such as catecholaminergic polymorphic ventricular tachycardia. We have gained new insights into the recurrence of ventricular arrhythmias in the setting of various conditions such as myocarditis and inherited cardiomyopathic disorders. Novel computational approaches may help predict occurrence of ventricular arrhythmias and localize arrhythmias to guide ablation. There are further advances in our understanding of noninvasive radiotherapy. We have increased our understanding of the role of His bundle pacing and left bundle branch area pacing to maintain synchronous ventricular activation. There have also been significant advances in the defibrillators, cardiac resynchronization therapy, remote monitoring, and infection prevention. There have been advances in our understanding of the pathways and mechanisms involved in atrial and ventricular arrhythmogenesis.

Primary Outcome Evaluation of a Next-Generation Left Atrial Appendage Closure Device: Results From the PINNACLE FLX Trial

BACKGROUND

Left atrial appendage (LAA) occlusion provides an alternative to oral anticoagulation for thromboembolic risk reduction in patients with nonvalvular atrial fibrillation. Since regulatory approval in 2015, the WATCHMAN device has been the only LAA closure device available for clinical use in the United States. The PINNACLE FLX study (Protection Against Embolism for Nonvalvular AF Patients: Investigational Device Evaluation of the Watchman FLX LAA Closure Technology) evaluated the safety and effectiveness of the next-generation WATCHMAN FLX LAA closure device in patients with nonvalvular atrial fibrillation in whom oral anticoagulation is indicated, but who have an appropriate rationale to seek a nonpharmaceutical alternative.

METHODS

This was a prospective, nonrandomized, multicenter US Food and Drug Administration study. The primary safety end point was the occurrence of one of the following events within 7 days after the procedure or by hospital discharge, whichever was later: death, ischemic stroke, systemic embolism, or device- or procedure-related events requiring cardiac surgery. The primary effectiveness end point was the incidence of effective LAA closure (peri-device flow ≤5 mm), as assessed by the echocardiography core laboratory at 12-month follow-up.

RESULTS

A total of 400 patients were enrolled. The mean age was 73.8±8.6 years and the mean CHA₂DS₂-VASc score was 4.2±1.5. The incidence of the primary safety end point was 0.5% with a 1-sided 95% upper CI of 1.6%, meeting the performance goal of 4.2% (P<0.0001). The incidence of the primary effectiveness end point was 100%, with a 1-sided 95% lower CI of 99.1%, again meeting the performance goal of 97.0% (P<0.0001). Device-related thrombus was reported in 7 patients, no patients experienced pericardial effusion requiring open cardiac surgery, and there were no device embolizations.

CONCLUSIONS

LAA closure with this next-generation LAA closure device was associated with a low incidence of adverse events and a high incidence of anatomic closure. Registration: URL: https://www.clinicaltrials.gov; Unique identifier: NCT02702271.

Multiparameter diagnostic sensor measurements during clinically stable periods and worsening heart failure in ambulatory patients

Aims

This study aims to characterize the range of implantable device‐based sensor values including heart sounds, markers of ventilation, thoracic impedance, activity, and heart rate for patients with heart failure (HF) when patients were deemed to be in clinically stable periods against the time course of acute decompensation and recovery from HF events.

Methods and results

The MultiSENSE trial followed 900 patients implanted with a COGNIS CRT‐D for up to 1 year. Chronic, ambulatory diagnostic sensor data were collected and evaluated during clinically stable periods (CSP: unchanged NYHA classification, no adverse events, and weight change ≤2.27 kg), and in the timeframe leading up to and following HF events (HF admissions or unscheduled visits with intravenous HF treatment). Physiologic sensor data from 1667 CSPs occurring in 676 patients were compared with those data leading up to and following 192 HF events in 106 patients. Overall, the mean age was 66.6 years, and the population were predominantly male (73%). Patients were primarily in NYHA II (67%), with a mean LVEF of 29.6% and median NT‐proBNP of 754.5 pg/mL. Sensor values during CSP were poorer in patients who had HF events during the study period than those without HF events, including first heart sound (S1: 2.18 ± 0.84 mG vs. 2.62 ± 0.95 mG, P = 0.002), third heart sound (S3: 1.13 ± 0.36 mG vs. 0.91 ± 0.30 mG, P < 0.001), thoracic impedance (45.66 ± 8.78 Ohm vs. 50.33 ± 8.43 Ohm, P < 0.001), respiratory rate (19.09 ± 3.10 br/min vs. 17.66 ± 2.39 br/min, P = 0.002), night time heart rate (73.39 ± 8.36 b.p.m. vs. 69.56 ± 8.09 b.p.m., P = 0.001), patient activity (1.69 ± 1.84 h vs. 2.56 ± 2.20 h, P = 0.006), and HeartLogic index (11.07 ± 12.14 vs. 5.31 ± 5.13, P = 0.001). Sensor parameters measured worsening status leading up to HF events with recovery of values following treatment.

Conclusions

Device‐based physiologic sensors not only revealed progressive worsening leading up to HF events but also differentiated patients at increased risk of HF events when presumed to be clinically stable.

Glial cell line-derived neurotrophic factor is a key neurotrophin in the postnatal enteric nervous system

BACKGROUND

The enteric nervous system (ENS) continues its structural and functional growth after birth, with formation of ganglia and the innervation of growing smooth muscle. However, little is known about factors in the postnatal intestine that influence these processes.

METHODS

We examined the presence and potential role of glial cell line-derived nerve growth factor (GDNF) in the rat postnatal ENS using neonatal tissue, primary co-cultures of the myenteric plexus, smooth muscle, and glial cells as well as cell lines of smooth muscle or glial cells.

KEY RESULTS

Western blot analysis showed that GDNF and its co-receptors rearranged during transfection (RET) and GDNF family receptor alpha-1 were expressed in the muscle layer of the neonatal and adult rat intestine. Immunohistochemistry localized the receptors for GDNF to myenteric neurons, while GDNF was localized to smooth muscle cells. In a co-culture model, GDNF but not nerve growth factor, brain derived neurotrophic factor or neurotrophin-3 significantly increased neuronal survival and more than doubled the numbers of neurites in vitro. RT-PCR, qPCR, Western blotting, ELISA, and immunocytochemistry as well as bioassays of neuronal survival and of RET phosphorylation all identified intestinal smooth muscle as the source of GDNF in vitro. GDNF also induced morphological changes in the structure and organization of neurons and axons, causing marked aggregation of neuronal cell bodies and collinear development of axons. As well, GDNF (50-150 ng mL(-1)) significantly increased [(3)H]-choline uptake and stimulated [(3)H]-acetylcholine release.

CONCLUSIONS & INFERENCES

We conclude that GDNF derived from intestinal smooth muscle cells is a key factor influencing the structural and functional development of postnatal myenteric neurons.

Assessing recovery in middle cerebral artery stroke using functional MRI

PRIMARY OBJECTIVE

To understand the temporal evolution of brain reorganization during recovery from stroke.

RESEARCH DESIGN

A patient who suffered left middle cerebral artery stroke 9 months earlier was studied on three occasions, approximately 1 month apart.

METHODS AND PROCEDURES

Brain activation was studied using functional Magnetic Resonance Imaging (fMRI). During each session, the patient performed a finger-to-thumb opposition task, which involved one bimanual and two unimanual conditions. Each condition consisted of overt movement of fingers and imagery of the same task.

RESULTS

With recovery, greater recruitment was observed of the affected primary motor cortex (M1) and a decrease in activation of the unaffected M1 and supplementary motor area. In addition, the widespread activation of brain areas seen during the initial session changed to a more focused pattern of activation as the patient recovered. Imagery tasks resulted in similar brain activity as overt execution pointing to imagery as a potential tool for rehabilitation.

Evaluation of the sharpness of concentric needle electrodes by a penetration test

This paper deals with a method to evaluate the sharpness of the concentric needle electrode (CNE) and the consistency of sharpness on repeated penetration. An aluminum foil of standard thickness and properties was used as the penetration medium. A load profile was obtained as a function of time, and has been correlated with the shape and quality of grinding of the tip of the CNE. This load profile can be used as a quality evaluation method. This method is utilized for the assessment of the impairment of the needle tip on repeated penetration and hence for comparison of different needle electrode models.

Left atrial femoral bypass and cerebrospinal fluid drainage decreases neurologic complications in repair of descending and thoracoabdominal aortic aneurysms

This study was undertaken to evaluate the role of cerebrospinal fluid (CSF) drainage and left atrial to femoral artery (LAFA) bypass in preventing postoperative neurologic complications for patients who had undergone descending and thoracoabdominal aortic aneurysm (TAAA) repair. LAFA bypass and CSF drainage were used as adjuncts in the treatment of 8 patients with descending and 13 patients with TAAAs (December 1999 to March 2000). LAFA bypass was established with the use of a centrifugal Biomedicus pump. Distal flows were maintained between 1.5 and 2.5 L/min during the procedures. Mean LAFA bypass time was 40 (range, 21 to 60 min). The CSF pressure was kept below 10-12 mmHg during the operations and for the first 72 hr postoperatively. All patients received heparin (1 mg/kg), which was reversed at the completion of the procedure. Passive hypothermia (rectal temperature: 32 degrees-34 degrees C) was used in all cases. All patent T8-L1 intercostal arteries were reattached to the graft. There were 13 men and 8 women. The median age was 56 years (range, 49 to 78). Chronic aortic dissection was the cause of the aneurysm in 9 patients (43%), trauma in 1 patient (5%), and medial degeneration in 11 patients (52%). There were four type I (19%), four type II (19%), and five type III (24%) TAAA. In eight patients (38%) the entire descending thoracic aorta was aneurysmal. Our results showed that the use of CSF drainage and LAFA bypass prevents paraplegia/paraparesis after repair of thoracoabdominal and descending thoracic aneurysms.