Periprocedural Dynamics of Aortic Regurgitation in Patients Supported With an Impella Left Ventricular Assist Device.

OBJECTIVES: To determine the presence of and periprocedural changes caused by aortic regurgitation (AR) in patients supported with an Impella (Abiomed, Danvers, MA) left ventricular assist device. DESIGN: Retrospective. SETTING: Tertiary academic medical center. PARTICIPANTS: Patients who underwent insertion of an Impella device at Allegheny General Hospital from January 2015 to December 2018. INTERVENTIONS: Analysis of patient electronic medical records. MEASUREMENTS AND MAIN RESULTS: Demographic information; comorbidities; duration of support; and the presence and severity of AR pre-procedure and post-procedure, as reported by echocardiography, were analyzed. The electronic medical records of 69 patients were included in the present study. Before placement of the Impella device, 25 (35%) patients showed detectable AR, with 18 (26%) showing mild AR and 7 (10%) showing moderate AR. After the removal of the Impella device, AR remained steady or increased in 61 patients. Fifteen patients (22%) demonstrated mild AR, 6 (8.7%) demonstrated moderate AR, and 2 (2.9%) demonstrated severe AR. An increase in severity of AR was noted in 9 patients (14.7%), and 52 patients (85%) had no change in the severity of AR. The duration of support with the Impella device, demographic variables, and comorbidities were not associated with a statistically significant risk for increased severity of post-procedural AR in multiple multivariable logistic regression analyses. CONCLUSIONS: The presented data suggest that after Impella device support, a significant proportion of patients may show evidence of increased AR. Additional studies are needed to understand the etiology and significance of this observation.

Malignant Hyperthermia: Review of Diagnosis and Treatment during Cardiac Surgery with Cardiopulmonary Bypass.

Malignant hyperthermia is a potentially life-threatening hypermetabolic disorder, often induced by exposure to volatile anesthetics and succinylcholine. There are few reports of malignant hyperthermia during cardiopulmonary bypass. Here the authors review available literature including case reports of malignant hyperthermia and cardiopulmonary bypass and discuss the potential implications of malignant hyperthermia diagnosis and management as it applies to cardiac surgery.

Muscular body build and male sex are independently associated with malignant hyperthermia susceptibility.

PURPOSE: Malignant hyperthermia susceptibility (MHS) is a disorder of the regulation of calcium in skeletal muscle. Muscular individuals have been shown to have a 13.6-fold increased risk of death during malignant hyperthermia (MH) episodes and are more likely to experience a recurrence after initial treatment. Twenty-five percent of severe MH episodes have occurred in elite athletes. This study investigated the association between MHS and muscular body build. METHODS: Data were obtained from existing reports in the North American Malignant Hyperthermia Registry, including the Report of Muscle Biopsy and Contracture Testing (caffeine-halothane contracture test [CHCT]) as well as Adverse Metabolic or Muscular Reaction to Anesthesia (AMRA) reports. Malignant hyperthermia susceptible individuals were compared with MH negative individuals with regard to body build and reason for testing. Males were also compared with females. Both the CHCT and the AMRA forms were reviewed for comments. RESULTS: Of the 1,292 individuals diagnosed with MHS by CHCT, males were more likely to be diagnosed with the disorder than females (odds ratio [OR], 2.33; 95% confidence interval [CI], 1.99 to 2.7; P < 0.001). Muscular individuals were more likely to be diagnosed with MHS than non-muscular individuals (OR, 1.94; 95% CI, 1.51 to 2.49; P < 0.001). Males were more likely to be tested after having a possible MH episode (OR, 2.33; 95% CI, 1.45 to 2.1; P < 0.001). Logistic regression showed that male sex (OR, 2.28; 95% CI, 1.93 to 2.7; P < 0.001) and muscular body build (OR, 2.17; 95% CI, 1.21 to 3.9; P = 0.01) were independently predictive of MHS. The interaction between muscular body build and male sex was not significant (P = 0.13). Indications for testing, MH episode vs family history of MH, did not differ between muscular and non-muscular individuals (P = 0.44). Eight of 839 AMRAs and two reports of CHCT had comments describing athletic abilities. Ryanodine receptor type 1 (RYR1) gene mutations were found in five of these athletes. CONCLUSION: Muscular body build and male sex are strongly associated with MHS.

Long term oral Dantrolene Improved Muscular Symptoms in a Malignant Hyperthermia Susceptible Individual.

This case report describes a female with p.Lys4876Arg amino acid change in the ryanodine receptor type 1 (RYR1) and a sibling who died of malignant hyperthermia (MH) during anesthesia. After her diagnosis as MH susceptible, this patient was administered low-dose dantrolene daily for greater than 25 years for treatment of chronic muscle spasm and pain in her lower extremities and back limiting sleep. Her creatine phosphokinase (CPK) was as high as 2390 IU/L during labor and 900 IU at rest. With 25 mg dantrolene daily, muscle cramps were eliminated, and sleep was improved. Gait instability was noted with dantrolene in the morning, but not when taken at bedtime. There was no evidence of liver injury. This case suggests that low dose dantrolene by mouth could be considered for the treatment of chronic muscle pain in individuals with MH susceptibility.