Successful treatment of phrenic nerve injury with diaphragmatic plication 5 years after onset: A case report

Diaphragmatic paralysis due to phrenic nerve injury is an occasional complication of cardiothoracic surgery. Although diaphragmatic plication is widely used to treat patients with severe irreversible symptoms, its surgical indication and timing remain controversial. Here, we present a rare case of diaphragmatic paralysis in a 65-year-old woman who underwent cardiac surgery and whose respiratory symptoms worsened despite >5 years of conservative management. Consequently, she underwent diaphragmatic plication using an endostapler to resect the redundant diaphragm, followed by over-suturing of all staple lines. She was discharged without any complications and her symptoms and chest radiography and spirometry results improved postoperatively.

Phrenic Nerve Injury During Cryoballoon-Based Pulmonary Vein Isolation: Results of the Worldwide YETI Registry

Background: Cryoballoon-based pulmonary vein isolation (PVI) has emerged as an effective treatment for atrial fibrillation. The most frequent complication during cryoballoon-based PVI is phrenic nerve injury (PNI). However, data on PNI are scarce. Methods: The YETI registry is a retrospective, multicenter, and multinational registry evaluating the incidence, characteristics, prognostic factors for PNI recovery and follow-up data of patients with PNI during cryoballoon-based PVI. Experienced electrophysiological centers were invited to participate. All patients with PNI during CB2 or third (CB3) and fourth-generation cryoballoon (CB4)-based PVI were eligible. Results: A total of 17 356 patients underwent cryoballoon-based PVI in 33 centers from 17 countries. A total of 731 (4.2%) patients experienced PNI. The mean time to PNI was 127.7±50.4 seconds, and the mean temperature at the time of PNI was −49±8 °C. At the end of the procedure, PNI recovered in 394/731 patients (53.9%). Recovery of PNI at 12 months of follow-up was found in 97.0% of patients (682/703, with 28 patients lost to follow-up). A total of 16/703 (2.3%) reported symptomatic PNI. Only 0.06% of the overall population showed symptomatic and permanent PNI. Prognostic factors improving PNI recovery are immediate stop at PNI by double-stop technique and utilization of a bonus-freeze protocol. Age, cryoballoon temperature at PNI, and compound motor action potential amplitude loss >30% were identified as factors decreasing PNI recovery. Based on these parameters, a score was calculated. The YETI score has a numerical value that will directly represent the probability of a specific patient of recovering from PNI within 12 months. Conclusions: The incidence of PNI during cryoballoon-based PVI was 4.2%. Overall 97% of PNI recovered within 12 months. Symptomatic and permanent PNI is exceedingly rare in patients after cryoballoon-based PVI. The YETI score estimates the prognosis after iatrogenic cryoballoon-derived PNI. REGISTRATION: URL: https://www.clinicaltrials.gov ; Unique identifier: NCT03645577.

Right hemidiaphragmatic paralysis after cervical transforaminal epidural steroid injection: illustrative case

BACKGROUND Cervical radiculopathy is a common cause of neck pain, with radiation into the upper extremity in a dermatomal pattern. Corticosteroid injection is a conservative management option with a low risk of major adverse events. No reviewed literature or case reports have implicated phrenic nerve injury secondary to cervical transforaminal epidural steroid injection (CTFESI). OBSERVATIONS A 45-year-old man with severe right C6 radiculopathy secondary to a large right-sided C5–6 herniated intervertebral disc presented to the pain management clinic, where he received a right-sided C6 CTFESI. An hour after injection, the patient experienced shortness of breath, which was found to be caused by right diaphragmatic paralysis. The patient underwent a C5–6 anterior cervical discectomy and fusion, which provided complete relief of his radicular symptoms. However, the right hemidiaphragmatic paralysis remained at the 1-year postoperative visit. LESSONS Thorough literature review showed no established explanations for phrenic nerve injury after CTFESI. In this study, the authors explored the suspected mechanisms of possible injury to the phrenic nerve. Epidural corticosteroid injection is considered to be a safe option for conservative management of cervical radiculopathy. This study unveiled a unique and important adverse event that should be considered before a patient receives CTFESI.

Abstract 13686: Increased Right Superior Pulmonary Vein Ovality is Associated With Phrenic Nerve Injury in Patients Undergoing Cryoablation for Atrial Fibrillation

Introduction: Success of cryoablation for atrial fibrillation (AF) requires creation of continuous, circumferential lesions around the pulmonary veins (PVs). The depth of these cryo-lesions depends on tissue contact, balloon location, ablation duration and nadir temperature. An optimum lesion depth must be achieved such that effective isolation occurs without collateral cryothermal damage to surrounding structures eg, phrenic nerve injury (PNI). Hypothesis: Increased RSPV ovality results in poor pairing between the balloon and PV, which may cause deeper freezing at the lateral circumference of the PV antrum, near the course of the phrenic nerve, resulting in PNI. Methods: Consecutive patients undergoing cryoablation for paroxysmal/persistent AF were included. Pre-procedural cardiac CT scans were analyzed to evaluate PV size (diameters, cross-sectional area, circumference) and ovality (ratio of maximum:minimum diameter (d max :d min ), shape). Effects of these anatomic characteristics on rates of complications were analyzed. Results: RSPVs from 310 patients (age 65.2 years, 38.1% female, 43.2% persAF) were studied. RSPVs were the largest of the 4 normal PVs (d max 21.5±4 mm; d min 17.8±3.8 mm; area 309±113 mm 2 ; circumference 124.2±22.8 mm). A majority of RSPVs were round (57.3% round, 26.9% oval and 15.9% flat), with median d max :d min = 1.18 [1.1-1.32]. PNI was the 2nd most common complication (after access-site complications). Transient diaphragmatic palsy occurred in 2.9% of patients; there were no cases of complete or persistent diaphragmatic paralysis. Patients in whom diaphragmatic palsy occurred had more oval veins (median d max :d min 1.35 [1.23-1.5] vs 1.18 [1.1-1.31]; p=0.015). Additionally, there was a significant difference in the proportion of patients with round RSPVs who had diaphragmatic palsy (1.1%) compared to those with oval or flat RSPVs (5.3%) (p=0.029) (Fig). Conclusion: Increased RSPV ovality is associated with phrenic nerve injury.

A simple method to detect phrenic nerve impairment during cryoballoon ablation of atrial fibrillation using aVF in the standard surface ECG

Background Phrenic nerve palsy (PNP) is the most common complication in cryoballoon ablation of atrial fibrillation. Monitoring techniques such as compound motor action potential (CMAP) measurements using additional leads, or catheters positioned in the subdiaphragmatic hepatic vein or the esophagus have demonstrated to be effective to prevent PNP. Purpose This study investigates the safety and feasibility of a simple monitoring strategy using the lead aVF of the standard surface 12 lead ECG for CMAP monitoring to prevent PNP. Methods In 263 continuous patients undergoing cryoballoon ablation, a decapolar catheter was placed in the right subclavian vein to stimulate the phrenic nerve during ablation of the right sided pulmonary veins ([email protected] ms at 60 bpm). Capture was continuously monitored using the CMAP potential in the inferior aVF lead of the surface ECG and manually by palpation of the abdominal movement. The freeze was terminated early if the amplitude of the aVF signal decrease by >25% in three consecutive beats or if the diaphragmatic contraction decreased. Results Phrenic nerve injury documented by a reduction of the signal in aVF was observed in 13 of the 263 patients (5%) during freezes of the right superior pulmonary vein. Reduced diaphragmatic contraction detected by palpation of the abdomen was never observed without previous reduced amplitude in the surface aVF signal and was therefore never the trigger to stop a freeze. In patients with phrenic nerve injury, the mean initial amplitude was 1mV (SD ±0.3mV) and the mean minimal amplitude was 0.3mV (SD ±0.2mV). Mean time to recovery of the aVF amplitude was 160 seconds. Twelve patients (4.6%) showed complete recovery whereas one patient (0.4%) showed only partial recovery, as demonstrated in a sniff test at the end of the procedure. This patient showed no clinical signs of phrenic nerve palsy the following day, and full recovery was demonstrated in a sniff test 3 months later. Conclusion Monitoring of CMAP using the aVF signal from a standard 12-lead ECG during phrenic nerve stimulation to reduce the incidence of phrenic nerve palsy is safe and feasible. This technique is readily available during every standard ablation without placing additional electrodes and more sensitive than manual palpation. aVF signal before and during ablation Funding Acknowledgement Type of funding source: None