Myxoma producing right-sided inflow and outflow obstruction

Right Ventricular Outflow Tract Obstruction in Adults: A Systematic Review and Meta-analysis

Background

Right ventricular outflow tract obstruction (RVOTO) is a cause of hemodynamic instability that can occur in several situations, including cardiac surgery, lung transplantation, and thoracic surgery, and in critically ill patients. The timely diagnosis of RVOTO is important because it requires specific considerations, including the adverse effects of positive inotropes, and depending on the etiology, the requirement for urgent surgical intervention.

Methods

The objective of this systematic review and meta-analysis was to determine the prevalence of RVOTO in adult patients, and the distribution of all reported cases by etiology.

Results

Of 233 available reports, there were 229 case reports or series, and 4 retrospective cohort studies, with one study also reporting a prospective cohort. Of 291 reported cases of RVOTO, 61 (21%) were congenital, 56 (19%) were iatrogenic, and 174 (60%) were neither congenital nor iatrogenic (including intracardiac tumour). The mechanism of RVOTO was an intrinsic obstruction in 169 cases (58%), and an extrinsic obstruction in 122 cases (42%). A mechanical obstruction causing RVOTO was present in 262 cases (90%), and 29 cases of dynamic RVOTO (10%) were reported. In the 5 included cohorts, with a total of 1122 patients, the overall prevalence was estimated to be 4.0% (1%-9%).

Conclusions

RVOTO, though rare, remains clinically important, and therefore, multicentre studies are warranted to better understand the prevalence, causes, and consequences of RVOTO.

Myocardial infarction as complication of left atrial myxoma

Although cardiac myxomas are histologically benign, they tend to form emboli and cause intracardiac obstruction, so that they must be classified as potentially fatal tumors of the heart. The probability of arterial embolism is closely correlated with the morphology of the tumor. Thus, villous myxomas are more fragile and form emboli more often. Nuclear spin tomography and echocardiographic cine-mode sequences provide impressive images of the potential for embolism. It appears that coronary embolism may be more frequent in the group of myxoma patients than generally is assumed. These may present as acute myocardial ischemia with the typical clinical symptoms of acute myocardial infarction, as a silent infarct, shock, syncope or as sudden cardiac death. Besides our case report this paper will give an overview on published data on coronary embolism in patients with atrial myxoma. Interestingly there is a tendency for spontaneous recanalization of the obstructed coronary vessels, perhaps because of the tumors' tissue composition. Therefore it is reasonable to perform transoesophageal echocardiography to check out embolic sources like myxoma, when pathogenesis of myocardial infarction remains unclear after coronary angiography.