Cardiovascular Complications in Pheochromocytoma and Paraganglioma: Does Phenotype Matter?

BACKGROUND: Adrenaline-producing tumors are mostly characterized by a sudden release of catecholamines with episodic symptoms. Noradrenergic ones are usually less symptomatic and characterized by a continuous overproduction of catecholamines that are released into the bloodstream. Their effects on the cardiovascular system can thus be different. The aim of this study was to determine the prevalence of cardiovascular complications by catecholamine phenotype. METHODS: We retrospectively analyzed data on the prevalence of cardiovascular events in 341 consecutive patients with pheochromocytoma and paraganglioma treated from 1995 to 2023. Biochemical catecholamine phenotype was determined based on plasma or urinary catecholamines and metanephrines. RESULTS: According to the phenotype, 153 patients had noradrenergic pheochromocytoma and paraganglioma and 188 had adrenergic pheochromocytoma and paraganglioma. In the whole sample, the incidence of serious cardiovascular complications was 28% (95 patients), with no difference between the phenotypes or sexes. The noradrenergic phenotype had significantly more atherosclerotic complications (composite end point of type 1 myocardial infarction and symptomatic peripheral artery disease; odds ratio, 3.58 [95% CI, 1.59-8.83]; P=0.003), while the adrenergic phenotype more often had type 2 myocardial infarction and takotsubo-like cardiomyopathy (OR, 0.24 [95% CI, 0.09-0.57]; P=0.002). These changes remained even after adjustment for conventional risk factors of atherosclerosis. CONCLUSIONS: We found a 28% incidence of cardiovascular complications in a consecutive group of patients with pheochromocytoma and paraganglioma. Patients presenting with a noradrenergic phenotype have a higher incidence of atherosclerotic complications, while the adrenergic phenotype is associated with a higher incidence of acute myocardial damage due to takotsubo-like cardiomyopathy.

Hypermetabolism and Substrate Utilization Rates in Pheochromocytoma and Functional Paraganglioma.

The overproduction of catecholamines in pheochromocytoma/paraganglioma (PPGL) induces a hypermetabolic state. The aim of this study was to evaluate the incidence of a hypermetabolic state and differences in substrate metabolism in consecutive PPGL patients divided by catecholamine phenotype. Resting energy expenditure (REE) and respiratory quotient (RQ) were measured in 108 consecutive PPGL patients and 70 controls by indirect calorimetry. Hypermetabolic state was defined according to the Mifflin St. Jeor Equation as a ratio above 110%. Hypermetabolic state was confirmed in 70% of PPGL patients, regardless of phenotype. Older age, prevalence of diabetes mellitus and arterial hypertension were correlated with hypermetabolic PPGL as compared to normometabolic form. Analysis according to overproduced catecholamine showed differences in VCO2 (p < 0.05) and RQ (p < 0.01) and thus different substate metabolism between phenotypes in hypermetabolic form of PPGL. Lipid utilization was higher in the adrenergic phenotype (p = 0.001) and positively associated with the percentage of REE ratio (R = 0.48, p < 0.001), whereas the noradrenergic phenotype preferentially oxidizes carbohydrates (P = 0.001) and is correlated with the percentage of REE ratio (R = 0.60, p < 0.001). Hypermetabolic state in PPGL is a common finding in both catecholamine phenotypes. Hypermetabolic PPGL patients are older and suffer more from diabetes mellitus and arterial hypertension. Under basal conditions, the noradrenergic type preferentially metabolizes carbohydrates, whereas the adrenergic phenotype preferentially metabolizes lipids.

Gene Profile of Adipose Tissue of Patients with Pheochromocytoma/Paraganglioma.

Background: Brown adipose tissue (BAT) is a therapeutic target to combat obesity and related disorders. Pheochromocytoma and functional paraganglioma (PPGL) are associated with activated BAT due to catecholamine excess. Our aim was to evaluate BAT activity by gene profile and assess its relation to clinical characteristics and overproduced catecholamine. Methods: mRNA expression of 15 genes in subcutaneous adipose tissue (SAT) and visceral adipose tissue (VAT) was measured via RT-PCR in 25 patients with PPGL and 14 controls undergoing cholecystectomy. Results: We found in VAT of PPGL higher expression of UCP1 (p < 0.001), CEBPB, PPARGC1A (both p < 0.001), PRDM16 (p = 0.069) and DIO2 (p = 0.005). UCP1 expression correlated only with norepinephrine levels and its metabolite. UCP1 expression, among others, correlated negatively with BMI, age and positively with HDLc levels. Dominance of BAT or BeAT markers was not assessed in PPGL. In SAT of PPGL, we found higher expression of ADRB3, CIDEA (both p < 0.05), and PPARGC1A (p = 0.001), but not UCP1. Conclusion: We demonstrate signs of UCP1-dependent norepinephrine-induced thermogenesis connected with higher expression of DIO2, PPARGC1A, CEBPB and PRDM16 in retroperitoneal VAT of PPGL and its relations to circulating HDLc and triglycerides levels. However, no direct relationship with increased basal energy metabolism measured by calorimetry was found.

Postoperative adrenal insufficiency in Conn's syndrome-does it occur frequently?

Primary aldosteronism (PA) is the most frequent form of endocrine hypertension. Recently, frequent clinically significant adrenal insufficiency after adrenalectomy in subjects with PA has been reported, which may make the early postsurgical management difficult. We retrospectively searched for possible adrenal insufficiency in subjects who underwent adrenalectomy for PA and have measured cortisol in the early postoperative course. We included subjects with confirmed diagnosis of PA who underwent either posture testing (blood draw at 06:00 and 08:00) and/or adrenal venous sampling (AVS) (blood draw between 08:00 and 09:00) and have also measured cortisol after surgery (cortisol measured approximately at 07:00). Cortisol was measured by immunoassay. In this study, we identified 150 subjects (age 48.5 ± 10.3 years) with available cortisol values in the early postoperative course (median [25th percentile, 75th percentile]) 6 [5,6] days. Postoperative cortisol values (551 ± 148 nmol/l) were normal and significantly higher, compared to preoperative standing cortisol values (404 ± 150 nmol/l; (P < 0.001) and AVS cortisol values (493 ± 198 nmol/l; P = 0.009), and did not significantly differ from preoperative supine cortisol values. Postsurgical cortisol values were not different among subjects with or without abnormal dexamethasone suppression test or elevated urinary free cortisol pre-surgery, and were significantly higher in subjects with abnormal diurnal cortisol variability compared with subjects with normal diurnal variability. No patient presented with adrenocortical crisis in the later follow-up. In conclusion, postoperative cortisol values did not indicate any suspicion of possible adrenal insufficiency. To exclude possible adrenal insufficiency, it may be sufficient to measure morning cortisol in the early postoperative course.