Comparison of international normalized ratio determined by point-of-care to standard laboratory testing before and after reversal of heparin in cardiac surgery.

STUDY OBJECTIVE: To compare point-of-care (POC) of international normalized ratio to laboratory-derived values before and after cardiopulmonary bypass, with the primary aim of evaluating for any change in the relationship between the tests. METHODS: This is a prospective observational study with 50 patients undergoing cardiac surgery enrolled. The International normalized ratio measured at two time points, precardiopulmonary bypass and after heparin reversal with protamine using both POC i-STAT and standard laboratory analysis for both time points. A difference of 0.2 between tests at either time point was considered clinically significant based on previous literature. A paired t test was used to test for a changing or statistically significant mean difference between tests. At both time points values were categorized into absolute difference of more than 0.2 or less than 0.2, and a Fisher's exact test was used to determine if an association existed between heparin reversal and a difference more than 0.2. Bland-Altman plots were also evaluated for agreement. RESULTS: A statistically and clinically significant mean difference [0.09 vs. 0.25, difference -0.163 95% confidence interval (-0.25, -0.08), P = 0.003] was seen between the laboratory and POC tests when pre and postheparin reversal samples were compared. A significantly greater number of patients had a clinically relevant difference between the tests post compared with pre (four patients vs. 18 patients, P = 0.001). Linear regression analysis of the difference compared with the means, showed significant correlation suggesting the presence of a proportional bias (pre r = 0.488, P = <0.01, post r = 0.571, P = <0.01). CONCLUSION: Clinically significant differences exist between POC and laboratory testing of international normalized ratio after heparin reversal during cardiac surgery. ClinicalTrials.gov Identifier NCT03267823.

Choosing the anesthetic and sedative drugs for supraventricular tachycardia ablations: A focused review.

This study provides a review of the contemporary literature for the effects of most commonly used anesthetic drugs for sedation and anesthesia during adult electrophysiologic (EP) studies where supraventricular tachycardias (SVT) need to be induced for diagnostic purposes and/or catheter ablation. Some medications may affect cardiac electrophysiology and conduction, altering the ability to induce the arrhythmia, and may have negative impact on mapping and ablation treatment. The objective of the study is to determine the best sedative choice during SVT ablations. The authors searched MEDLINE, PubMed, and Google Scholar databases for published articles within the past 20 years (1998-2018) that have evaluated the effects of common anesthetic drugs during SVT ablations. Further articles were identified through crossreferencing, discussion with electrophysiologists, and hand-searching key electrophysiology and anesthesia journals. Eight review articles, two randomized control trials, six prospective observational studies, one retrospective observational study, and two case reports were included in this review. Seven of the studies focused on the pediatric population. The findings about the effects of the commonly used anesthetics are discussed further in detail. Sevoflurane had no clinically important effects on sinoatrial (SA) node activity, or the normal atrioventricular (AV), or accessory pathway. Midazolam and fentanyl, alone or in combination, neither alter the inducibility of reentrant tachycardia nor have they shown to affect the SA node, refractory periods of AV conduction, or accessory pathways. Similar findings were reported by investigators with propofol, except for ectopic atrial tachycardia in children, which remained un-inducible in one of the studies. Remifentanil and dexmedetomidine lengthened both sinus cycle and AV conduction. Dexmedetomidine increased the atrial refractory period and diminished atrial excitability. Ketamine shortened atrial conduction and successfully returned prolongation of sinus node conduction due to dexmedetomidine. In conclusion, the current literature regarding sedation for SVT studies in the adult population is sparse. Midazolam, propofol, fentanyl, and remifentanil can be used safely in patients undergoing EP studies without significant interference with electrophysiological variables or the inducibility of reentrant tachycardias in usual clinical doses. Low-dose ketamine has potential use as an adjunctive medication in the EP lab and additional studies would be beneficial. The effects of dexmedetomidine on conduction and arrhythmia inducibility during SVT ablation is not as clear as studies have yielded conflicting results, and may not be the best choice for sedation in this patient population.

Anticoagulation and Antiplatelet Strategies After On-X Mechanical Aortic Valve Replacement.

BACKGROUND: The burden oral anticoagulation is a limitation of mechanical valve prostheses. OBJECTIVES: The aim of this study was to test whether patients could be safely managed with dual-antiplatelet therapy (DAPT) (aspirin 325 mg and clopidogrel 75 mg) or lower warfarin after On-X mechanical aortic valve replacement (mAVR). METHODS: PROACT (Prospective Randomized On-X Anticoagulation Trial) (n = 576) is a multicenter (41 sites) noninferiority trial. From June 2006 through February 2014, 201 patients ≥18 years of age without thromboembolic risk factors undergoing mAVR were randomized to receive DAPT (n = 99) or standard warfarin plus aspirin (n = 102) 3 months after mAVR (low-risk arm). From June 2006 through October 2009, 375 patients with 1 or more thromboembolic risk factors were also randomized to lower intensity warfarin plus aspirin (international normalized ratio 1.5 to 2.0; n = 185) or standard warfarin plus aspirin (international normalized ratio 2.0 to 3.0; n = 190) 3 months after mAVR (high-risk arm). RESULTS: The low-risk arm was terminated for excess cerebral thromboembolic events (3.12% per patient-year vs. 0.29% per patient-year, p = 0.02) in the DAPT group at up to 8.8-year follow-up (631.6 patient-years), with no differences in bleeding or all-cause mortality. High-risk arm patients experienced significantly lower major (1.59% per patient-year vs. 3.94% per patient-year, p = 0.002) and minor (1.27% per patient-year vs. 3.49% per patient-year, p = 0.002) bleeding up to 8.7-year follow-up (2,035.2 patient-years), with no differences in thromboembolism (0.42% per patient-year vs. 0.09% per patient-year, p = 0.20) and all-cause mortality. CONCLUSIONS: DAPT was associated with higher rates of thromboembolism and valve thrombosis compared with control in the low-risk arm. International normalized ratios were safely maintained at 1.5 to 2.0 in high-risk patients, without differences in mortality or thromboembolic complications. (Randomized On-X Anticoagulation Trial [PROACT]; NCT00291525).

Pearls of Wisdom for High-Risk Laser Lead Extractions: A Focused Review.

Due to new indications and improved technology, the incidence of laser lead extraction (LLE) has significantly increased over the past years. While LLE has been well studied and proven to be safe and effective, only few studies are geared toward the anesthesiologist's role during high-risk LLEs. This article utilized both a focused review and authors' experience to investigate anesthetic protocols during LLEs. Through this review, we recommend best practices for the anesthesiologist including appropriate procedure location, onsite availability of a cardiac surgeon, availability of a cardiopulmonary bypass machine, and intraoperative use of echocardiography to detect and address potential complications during high-risk LLEs.

Extracorporeal membrane oxygenation for repair of tracheal injury during transhiatal esophagectomy.

Extracorporeal Membrane Oxygenation (ECMO) for repair of tracheal injury during transhiatal esophagectomy Tracheal injury is a rare but potentially fatal complication of esophagectomies requiring prompt recognition and treatment. We describe a case of tracheal injury recognized in the operative period of an open transhiatal esophagectomy for squamous cell carcinoma of the mid to distal esophagus. When injury was discovered, attempts to improve oxygenation and ventilation by conventional methods were unsuccessful. Therefore, peripheral ECMO was used to support oxygenation during the tracheal defect repair. The use of ECMO for the repair of a tracheal injury during esophagectomy is very uncommon but, in our case, provided adequate oxygenation and ventilation while the surgeon repaired the injury and the patient was able to be promptly weaned from ECMO support and extubated not long after.

Transesophageal echocardiography-guided thrombectomy of intracardiac renal cell carcinoma without cardiopulmonary bypass.

Advanced renal cell carcinoma (RCC) resection has important anesthetic management implications, particularly when tumor extends, suprahepatic, into the right atrium. Use of transesophageal echocardiogram (TEE) is essential in identifying tumor extension and guiding resection. Latest surgical approach avoids venovenous and cardiopulmonary bypass yet requires special precautions and interventions on the anesthesiologist's part. We present a case of Level IV RCC resected without cardiopulmonary bypass and salvaged by TEE guidance and detection of residual intracardiac tumor.

Reduced anticoagulation after mechanical aortic valve replacement: interim results from the prospective randomized on-X valve anticoagulation clinical trial randomized Food and Drug Administration investigational device exemption trial.

OBJECTIVE: Under Food and Drug Administration investigational device exemption, the Prospective Randomized On-X Anticoagulation Clinical Trial (PROACT) has been testing the safety of less aggressive anticoagulation than recommended by the American College of Cardiology/American Heart Association guidelines after implantation of an approved bileaflet mechanical valve. METHODS: In this first limb of the PROACT, patients with elevated risk factors for thromboembolism were randomized at 33 US centers to receive lower dose warfarin (test international normalized ratio [INR], 1.5-2.0) or continue standard warfarin (control INR, 2.0-3.0), 3 months after mechanical aortic valve replacement. The INR was adjusted by home monitoring; all patients received 81 mg aspirin daily. Adverse events were independently adjudicated. RESULTS: A total of 375 aortic valve replacement patients were randomized into control (n = 190) and test (n = 185) groups from September 2006 to December 2009. The mean age ± standard deviation was 55.2 ± 12.5 years; 79% were men; and 93% were in sinus rhythm preoperatively. Calcific degeneration was present in 67%; active endocarditis was excluded. Concomitant procedures included coronary artery bypass grafting (27%), aortic aneurysm repair (14%), and other (25%). The follow-up duration averaged 3.82 years (755.7 patient-years [pt-yrs] for control; 675.2 pt-yrs for test). The mean INR was 2.50 ± 0.63 for the control and 1.89 ± 0.49 for the test groups (P < .0001). The test group experienced significantly lower major (1.48% vs 3.26%/pt-yr; P = .047) and minor (1.32% vs 3.41%/pt-yr; P = .021) bleeding rates. The incidence of stroke, transient ischemic attack, total neurologic events, and all-cause mortality were similar between the 2 groups. CONCLUSIONS: INR can be safely maintained between 1.5 and 2.0 after aortic valve replacement with this approved bileaflet mechanical prosthesis. With low-dose aspirin, this resulted in a significantly lower risk of bleeding, without a significant increase in thromboembolism.