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Vascular and Interventional Radiology: William W. Mayo-Smith and Damian E. Dupuy Adrenal Neoplasms: CT-guided Radiofrequency Ablation—Preliminary Results Radiology 2004; 231: 225-230 [Abstract] [Full text] [PDF]

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Hypertension during radiofrequency ablation of pheochromocytoma

Bradford J. Wood, MD   (24 May 2004)

Hypertension during radiofrequency ablation of pheochromocytoma 24 May 2004
Bradford J. Wood, MD, Radiologist National Institutes of Health Send letter to journal: Re: Hypertension during radiofrequency ablation of pheochromocytoma bwood{at}nih.gov Bradford J. Wood, MD	Editor: I read with interest the nice work of Mayo-Smith and Dupuy (1), which is a valuable addition to the literature. The issue of hypertensive crisis during adrenal radiofrequency (RF) ablation has been described in one published case report with two patients (2) and in several others cases of lower-right-lobe liver RF ablation or adrenal RF ablation reported verbally, without, as yet, peer-reviewed verification. The issue of hypertensive crisis is interesting but can likely be safely managed by a well-informed anesthesia and radiology team. One case was particularly instructive regarding management of induced hypertension. We reported a case of hormonally active pheochromocytoma metastatic to a rib that was treated with RF ablation (3). We measured serial serum catecholamine levels during this treatment, and it was interesting to note that the blood pressure and serum catecholamine levels were intimately temporally related to the current in the RF ablation generator, with a delay of several seconds to less than a minute between manipulation of the current and clinical (blood pressure) and laboratory (serum catecholamine) response. During the course of treatment, the RF generator was turned on and kept initially at a low current for a few seconds, with gradual incremental increase until systolic blood pressure reached 20 mm Hg above baseline. At that time, the current was turned off and nitroprusside drip turned up to accommodate the increased pressure. The RF ablation was stopped each time blood pressure rose above 180 mm Hg systolic, until treatment could be performed for a 6-minute period with tissue temperatures greater than 70°C during the cooling phase with a saline-cooled tip needle. Of note, this patient was receiving a multiple-medication blockade, including alpha blockade, beta blockade, and metyrosine (a tyrosine hydroxylase inhibitor that blocks the first transformation in catecholamine biosynthesis). Metyrosine can take days to weeks to load and titrate. It is vital that the anesthesia team be aware of the timing issues and ready with an arterial line for blood pressure monitoring and a nitroprusside drip. Our group has a protocol under review for treatment of von Hippel-Lindau-associated pheochromocytomas with RF ablation that may shed further light on this issue. It is likely that this risk can be managed with careful attention to technique detail. References 1. Mayo-Smith WW, Dupuy DE. Adrenal neoplasms: CT-guided radiofrequency ablation—preliminary results. Radiology 2004; 231:225-230. 2. Onik G, Onik C, Medary I, et al. Life threatening hypertensive crises in two patients undergoing hepatic radiofrequency ablation. AJR Am J Roentgenol 2003; 181:495-49. 3. Pacek K, Fojo T, Goldstein DS, et al. Radiofrequency ablation (RFA): a novel approach for the treatment of metastatic pheochromocytoma. J Natl Cancer Inst 2001;93:648-649. Dr Mayo-Smith responds: We appreciate the insightful letter from Dr Wood in which he refers to his experience performing RF ablation of a hormonally active pheochromocytoma metastasis to a rib (1). In this experience, they noted that the patient’s systemic blood pressure and serum catecholamine levels were temporally related to the current applied by the RF generator when treating the metastasis. We treated one patient with an adrenal pheochromocytoma who had received prophylactic alpha and beta blockade, and this patient did not exhibit systemic increase in blood pressure, although we did not measure serum catecholamine levels (2). As Dr Wood notes and we address in our addendum, Onik and colleagues described episodes of hypertension due to an RF ablation performed in a liver lesion adjacent to a normal adrenal gland in two patients (3). While we view alpha and beta blockade with an anesthesiologist present as a requirement for treating pheochromocytomas and (based on the work of Wood and colleagues) pheochromocytoma metastases, it is interesting that our 11 treatments of adrenal metastases did not result in episodes of hypertension. This may be because the metastases destroyed normal adrenal tissue, thereby preventing excess catecholamine release. Thus, the level of alpha and beta blockade required before adrenal RF ablation appears to vary depending on the type of adrenal tumor treated. It should also be noted that pretreatment with alpha and beta blockade carries its own set of risks. Because of the nature of the disease, patients with adrenal metastases are an older population that is at risk for hypotension when alpha and beta blockade are applied. A noninvasive test to determine which patients might be at risk for malignant hypertension during adrenal RF ablation would be useful but, to our knowledge, does not exist. References 1. Pacek K, Fojo T, Goldstein DS, et al. Radiofrequency ablation (RFA): a novel approach for the treatment of metastatic pheochromocytoma. J Natl Cancer Inst 2001;93:648-649. 2. Mayo-Smith WW, Dupuy DE. Adrenal neoplasms: CT-guided radiofrequency ablation—preliminary results. Radiology 2004; 231:225-230. 3. Onik G, Onik C, Medary I, et al. Life threatening hypertensive crises in two patients undergoing hepatic radiofrequency ablation. AJR Am J Roentgenol 2003; 181:495-497.