Response to Delay in the Diagnosis of Conn’s Syndrome: A Single-Center Experience Over 30 Years
Dhanjal and Beevers1 raised some interesting issues concerning our study on predictors of outcome in aldosterone-producing adenoma (APA) patients postadrenalectomy. Consistent with our findings, they also found that a long known duration of hypertension was common before APA could be diagnosed and treated by adrenalectomy. Interestingly, they noticed that this long duration, ≈8 years, before undertaking adrenalectomy was mainly because of the delay in referring the hypertensive patients from the primary care setting to the tertiary centers. This observation accords well with our data: the average time from referral to adrenalectomy in our APA cases was 6 months, and, therefore, most of the known duration of hypertension can be attributed to a delayed suspicion of primary aldosteronism and/or a delayed referral to a tertiary center.
Moreover, this is not at all surprising, because primary aldosteronism, albeit being the most common endocrine cause of hypertension, often masquerades itself as “essential hypertension,” as Conn et al2 pointed out many years ago. Data obtained in hypertensive patients screened by general practitioners in the Bussolengo Study suggested a high prevalence of primary aldosteronism at the primary care setting3; more recently this high prevalence was demonstrated in the Prevalence of Primary Aldosteronism in Hypertension Study, the largest prospective investigation of referred hypertensive subjects, where 4.8% of 1125 consecutive patients were eventually confirmed to have an APA.4 This study also testified the difficulty of suspecting the diagnosis, because the majority of the patients eventually confirmed to have an APA had neither hypokalemia nor severe/resistant hypertension or any other stigmata that may raise the suspicion of the presence of this common curable cause of hypertension.4 Hence, a high degree of alert on the possibility of APA and a widespread use of screening tests for this condition are to be advised to attain an early diagnosis, as we suggested recently.5
In the study that Dhanjal and Beevers1 commented on, we verified the hypothesis that the time-dependent process of vascular remodeling, featuring an increased media/lumen ratio of resistance arteries, predicted a poorer blood pressure response to adrenalectomy. Unexpectedly, we could find no significant collinearity between the media/lumen ratio and the known duration of hypertension, suggesting that the former is not simply the result of long-standing hypertension but more likely reflects several mechanisms, including the degree of aldosterone excess and an individual susceptibility to developing vascular damage. Nonetheless, there was no question that correction of primary aldosteronism was achieved in all of the APA patients and that both an increased media/lumen ratio of resistance arteries and a known duration of hypertension >38 months implied a slimmer chance of achieving normotension postadrenalectomy. Hence, given the fact that an early diagnosis is prejudicial for curing hypertension and the longest delay could be attributed to a late referral by a primary care setting, we totally agree with Dhanjal and Beevers1 that much effort should be put into promoting awareness of the high prevalence of APA among primary health care professionals to minimize the delay in diagnosis and adrenalectomy.
Sources of Funding
This study was supported by grant fundings from the Societá Italiana dell’Ipertensione Arteriosa, The Foundation for Advanced Research in Arterial Hypertension and Cardiovascular Diseases (F.O.R.I.C.A.), and the University of Padua.
Dhanjal TS, Beevers DG. Delay in the diagnosis of Conn’s syndrome: a single-center experience over 30 years. Hypertension. 2008; 52: e22.
Rossi GP, Bernini G, Caliumi C, Desideri G, Fabris B, Ferri C, Ganzaroli C, Giacchetti G, Letizia C, Maccario M, Mallamaci F, Mannelli M, Mattarello MJ, Moretti A, Palumbo G, Parenti G, Porteri E, Semplicini A, Rizzoni D, Rossi E, Boscaro M, Pessina AC, Mantero F. A prospective study of the prevalence of primary aldosteronism in 1,125 hypertensive patients. J Am Coll Cardiol. 2006; 48: 2293–2300.
Rossi GP, Bolognesi M, Rizzoni D, Seccia TM, Piva A, Porteri E, Tiberio GA, Giulini SM, Agabiti-Rosei E, Pessina AC. Vascular remodeling and duration of hypertension predict outcome of adrenalectomy in primary aldosteronism patients. Hypertension. 2008; 51: 1366–1371.