1. In a prospective cohort study of 51 patients with end-stage renal disease (ESRD) and severe secondary hyperparathyroidism (SHPT), ultrasound-guided percutaneous microwave ablation (MWA) of the parathyroid tissue was associated with significant reductions in serum PTH, calcium, and phosphorus compared to baseline.
2. There were no significant major complications during the procedure or during the follow-up period.
Evidence Rating Level: 2 (Good)
Study Rundown: Approximately one-third of patients with ESRD on long-term dialysis are affected by SHPT. While SHPT can be managed medically using vitamin D analogs and calcimimetic drugs, more severe uncontrolled cases require destruction of hyperplastic parathyroid tissue to mitigate sequelae, which include: increased bone fracture risk from renal osteodystrophy, increased vascular calcification, and higher mortality. Surgical intervention is often the treatment of choice but is limited due to anesthetic risks, failure to detect glands intraoperatively (thus requiring reoperation), and risk of permanent hypoparathyroidism. Thus, less invasive alternatives have the potential to broaden patient inclusion criteria while offering more rapid recovery. The purpose of this study was to evaluate whether ultrasound-guided MWA is a safe and efficacious alternative treatment option.
This study prospectively followed 51 patients with ESRD on dialysis who previously underwent surgical parathyroidectomy and who had known hyperplastic parathyroid tissue. All patients underwent a single session of MWA. The primary outcome of interest was post-operative serum levels of intact PTH, calcium, phosphate, and ALP. At the conclusion of the study, the patient cohort demonstrated statistically significant reductions in serum intact PTH, calcium, and phosphate post-MWA. Furthermore, MWA was not associated with any significant complications during or following the procedure. This suggests MWA is a viable, minimally invasive procedure for treatment of SHPT. However, the study was limited by its relatively small sample, the short follow-up, and the lack of post-MWA 99mTc-sestamibi sequence to verify lower parathyroid hormone activity. Future multi-center investigations with increased clinical follow-up periods are needed to validate the use of MWA in patients with severe SHPT.
In-Depth [prospective cohort]: The study prospectively analyzed the safety and efficacy of 51 patients that underwent MWA for severe secondary hyperparathyroidism from a single center in Beijing, China. All patients had ESRD on dialysis, high serum intact PTH levels, and > 1 enlarged parathyroid. All patients had previous surgical treatment and ongoing long-term treatment with oral calcitriol and/or calcium carbonate. Serum levels of intact PTH, calcium, phosphorus, and ALP were also obtained pre-MWA and post-MWA; paired sample-t tests were conducted for calcium and phosphate levels and Wilcoxon signed-rank tests were performed on intact PTH and ALP levels. At the study’s conclusion, all 51 patients (96 total parathyroid glands) had been successfully ablated through ultrasound-guided MWA during single treatment sessions. MWA treatment time for a single gland ranged from 63 to 705 seconds (mean: 216.1 +/- 130.1 seconds). Successful ablation was confirmed through pre-MWA vs. post-MWA contrast-enhanced ultrasound. Furthermore, there was significant reductions in intact PTH (mean: 1203 vs. 400 pg/mL; p < 0.01), serum calcium (mean: 2.53 vs. 2.33 mmol/L; p < 0.01), and serum phosphorus (mean: 1.97 vs. 1.54 mmol/L; p < 0.01) after a mean follow-up time of 11.1 months. There were no significant complications, except for one hematoma, occurred during the procedure and through the follow-up period. One patient was found to have ipsilateral laryngeal nerve injury verified at laryngoscopy.
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