Effect of Dose to the Heart and Cardiac Substructures on Cardiac Toxicity after Breast Cancer Radiation

PURPOSE/OBJECTIVE(S)

Pre-existing cardiovascular disease, chemotherapy, and higher mean heart dose are known risk factors for cardiac toxicity after breast radiation therapy. However, the relationship between cardiac substructure radiation exposure and toxicity is not well understood. We hypothesized that mean heart dose is a surrogate for global cardiac radiation exposure but that more specific dosimetric thresholds for the heart and its substructures could be identified, which could be used to guide radiation planning for breast cancer patients in the future.

MATERIALS/METHODS

In this cohort study, all breast cancer patients who received curative intent breast or chest wall radiotherapy at a single high-volume institution in 2014 and 2017 were included (n = 841). Baseline characteristics included hormone therapy, chemotherapy, menopausal status, diabetes, dyslipidemia, pre-existing cardiac toxicity, and age at diagnosis. Outcomes included any cardiac toxicity, arrhythmia, cardiomyopathy, ischemia, valvular, pericardial disease, and death. The heart and substructures, including left ventricle, right ventricle, left atrium, right atrium, aortic valve, pulmonic valve, mitral valve, tricuspid valve, and left anterior descending artery, were delineated on the simulation CT for each patient. Dosimetric variables, including mean dose, max dose, and V1, 2, 3, 4, 5, 10, 15, 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, and 70 Gy for the heart and substructures (in cc) were extracted. For each dosimetric variable, multivariable logistic regression was performed using baseline covariates in addition to the single dosimetric variable. Patients with missing data values were excluded. Results were combined and False Discovery Rate p-value correction was performed.

RESULTS

Multiple cardiac substructure dosimetric variables were associated with increased risk of mortality on multivariable analysis (p < 0.05). For left atrium and right atrium, V2, 3, 4, and 5 Gy were all significant. For right ventricle, mean dose, V1, 2, 3, 4, 5, 10, 15, 20, 25, 30, and 35 Gy were significant. For mitral valve, mean dose, max dose, V3, 4, and 5 Gy were significant. For tricuspid valve, mean dose was significant. For aortic valve, max dose, mean dose, V4, and V5 Gy were significant. For the whole heart, V1, 2, 3, 4, 5, 10, 15, 20, 25, 30, and 35 Gy were significant.

CONCLUSION

We have identified multiple dosimetric variables for the heart and its substructures which were associated with increased risk of mortality after breast cancer radiation. In fact, for certain structures, there were multiple exposure thresholds which showed increased risk of toxicity, highlighting the complex relationship between substructure dose and outcomes. Further study into these relationships will identify the most critical cardiac substructure constraints that could be used in radiation treatment planning.

The current status of lung transplantation: a nursing perspective

Since the first lung transplantation was attempted in 1963, the use of the procedure has gradually increased. The first successful operation was performed in 1983, and during the past decade the number of lung transplantations and heart-lung transplantations has increased rapidly, with 75% of recipients surviving past the first year. Chronic rejection is the greatest obstacle to long-term survival. In this article, a brief history of lung transplantation is provided. Recipient selection criteria are reviewed, together with the listing process and donor organ criteria. Recommendations for care of patients before and after lung transplantation are outlined, with a description of the postoperative course, including complications, pain control, rehabilitation, discharge procedures, and outpatient treatment.

Right and left ventricular dysfunction in patients with severe pulmonary disease

OBJECTIVE

To determine the prevalence of right and left ventricular dysfunction in a prescreened population of patients with severe pulmonary disease, and to analyze the relationship between right and left ventricular function.

DESIGN

Retrospective record review of 434 patients with severe pulmonary disease.

PATIENTS

Patients with end-stage pulmonary disease, including alpha1-antitrypsin deficiency emphysema, COPD, cystic fibrosis (CF), idiopathic pulmonary fibrosis, and pulmonary hypertension (primary and Eisenmenger's syndrome), who were evaluated for lung transplantation between January 1993 and December 1995.

MEASUREMENTS

Pulmonary function tests, arterial blood gases, radionuclide ventriculography, two-dimensional transthoracic echocardiography, pulmonary hemodynamics, coronary angiography.

RESULTS

Right ventricular dysfunction (right ventricular ejection fraction [RVEF] <45%) was present in 267 patients (66%), but the prevalence was highest (94%) in patients with pulmonary vascular disease. Among the patients with airway or parenchymal lung disease, the prevalence ranged from 59% in COPD to 66% in CF. In contrast, left ventricular dysfunction (left ventricular ejection fraction [LVEF] <45%) was present in only 6.4%, but it, too, was most common in the group with pulmonary hypertension (19.6%). In the groups with parenchymal or airway disease, the prevalence was 3.6%, and there was no statistical difference among the four diagnoses (alpha1-antitrypsin deficiency emphysema; COPD; CF; idiopathic pulmonary fibrosis). LVEF showed a significant correlation with RVEF (r=0.44; p<0.05), and left ventricular dysfunction was associated with the presence of moderate-to-severe tricuspid regurgitation but not with coronary artery disease. In a subset of patients with both right and left ventricular dysfunction who subsequently underwent lung transplantation, RVEF and LVEF increased pari passu after transplantation.

CONCLUSION

The prevalence of right ventricular dysfunction is high in patients with end-stage pulmonary disease, but the prevalence of left ventricular dysfunction is relatively low. Left ventricular dysfunction appears to be related to right ventricular dysfunction, perhaps through ventricular interdependence.

Comparison of the hemodynamics and survival of adults with severe primary pulmonary hypertension or Eisenmenger syndrome

BACKGROUND

To date, lung or heart-lung transplantation remains the only definitive treatment for most adults with severe primary pulmonary hypertension or Eisenmenger syndrome. Although the hemodynamic derangements and clinical history of adults with severe primary pulmonary hypertension have been well documented, those of adults with Eisenmenger syndrome have not.

METHODS

We evaluated hemodynamics and nontransplantation survival of 100 adults with severe pulmonary hypertension (34 +/- 9 years, 73 women and 27 men; 57 with primary pulmonary hypertension, 37 with Eisenmenger syndrome, and six with a previously repaired congenital heart defect) followed up by the lung transplant or adult congenital heart services at Washington University.

RESULTS

Despite a trend toward greater pulmonary artery pressures (107 +/- 20 versus 97 +/- 21 mm Hg, p = 0.06), patients with Eisenmenger syndrome had greater systemic cardiac indexes (2.7 +/- 0.6 versus 2.2 +/- 0.8 L/min/m2, p < 0.05) and lower mean right atrial pressures (5 +/- 2 versus 12 +/- 5 mm Hg, p < 0.0001) than patients with primary pulmonary hypertension. Four (11%) patients with Eisenmenger syndrome died and eight (22%) received transplants during the follow-up interval; 13 (23%) patients with primary pulmonary hypertension died, and 31 (54%) received transplants over the same interval. Actuarial survival of patients who did not receive transplants was 97% at 1 year, 89% at 2 years, and 77% at 3 years for patients with Eisenmenger syndrome and 77%, 69%, and 35%, respectively, for patients with primary pulmonary hypertension. Data on hemodynamics from a small number of patients with a previously repaired heart defect and severe pulmonary hypertension were similar to those from patients with primary pulmonary hypertension.

CONCLUSIONS

Our data suggest that adults with Eisenmenger syndrome have a more favorable hemodynamic profile and prognosis than adults with primary pulmonary hypertension.

Lung transplantation

Although the supply of donor organs remains extremely limited, improved methods of maintaining the lungs of potential donors to allow for transplantation are being developed along with improved techniques for lung preservation. Sufficient progress has been achieved to warrant continued application of lung transplantation for numerous types of end-stage pulmonary disease. As further refinements in lung transplantation techniques and postoperative management occur, there will be a greater need for advancing the knowledge and skills of nurses and other members of the interdisciplinary team. With improved resource management and quality outcomes, it is hoped that lung transplantation will be made available to a greater number of patients. All these continued advancements offer further challenges to improve patient care for lung transplant recipients.

Lung transplantation. Analysis of thirty-six consecutive procedures performed over a twelve-month period. The Washington University Lung Transplant Group

A consecutive series of 36 lung transplant procedures in 35 patients, performed over a 12-month period, has been reviewed. There were 14 men and 21 women undergoing 23 single, 12 bilateral, and one en bloc double lung transplant. There were one hospital death and three late deaths in the series, giving a hospital survival rate of 97.2% and a 1-year actuarial survival figure of 91.7%. Airway complications occurred in six patients (17.2%), one of whom died. Cytomegalovirus infection was demonstrated in 18 patients (51%), but no deaths have resulted. The most common cardiac complication was an atrial tachyarrhythmia (nine patients, 25.7%) and three patients had a cardiac arrest, but all were successfully resuscitated. Twelve patients required a further 25 surgical procedures after transplantation; however, renal and hematologic complications were uncommon. The prevalence and management of the other associated complications is discussed.