Anesthetic considerations for hepatic cryotherapy

Incidence of hypercoagulable events after image-guided percutaneous cryoablation of renal tumors: a single-center experience

PURPOSE

To identify retrospectively hypercoagulable events that occurred over time in patients who underwent image-guided percutaneous renal cryoablation and compare the incidence with a cohort of patients who underwent surgical partial nephrectomy (PN) during the same time period.

MATERIALS AND METHODS

An electronic medical record database was queried for patients who underwent percutaneous image-guided renal mass cryoablation or PN between September 2006 and June 2012. Records were examined for thrombotic events during the year following the procedure in each group. Incidence rates, Kaplan-Meier estimates, and patient demographic variables were compared using the stratified log-rank test and t test for independent samples.

RESULTS

The study comprised 114 cryoablation cases. The cumulative incidence of thrombotic events after 1 year was 4.39%. The incidence per 100 person-years was 4.84. There were 105 PN cases. The cumulative incidence of thrombotic events after 1 year was 1.0%. The incidence per 100 person-years was 1.14. The person-time incidence rate difference for these two groups did not reach statistical significance (P = .0894).

CONCLUSIONS

The incidence of thrombotic events in patients who underwent percutaneous renal cryoablation in this study was not significantly different than a comparable cohort who underwent surgical PN during the same time period.

Hemodynamic effects of laparoscopic radiofrequency ablation of liver tumors versus laparoscopic hepatic ultrasound examination

STUDY OBJECTIVE

To compare the hemodynamic changes that occur during laparoscopic radiofrequency ablation of liver metastases with those occurring during laparoscopic ultrasound hepatic examination alone.

DESIGN

Prospective, observational study.

SETTING

Operating rooms of a university-affiliated hospital.

PATIENTS

40 ASA physical status 2 and 3 patients with liver metastases.

INTERVENTIONS

20 patients underwent laparoscopic radiofrequency ablation of liver tumors following laparoscopic ultrasound examination, and 20 had laparoscopic ultrasound examination alone. The anesthetic technique was standardized.

MEASUREMENTS

The primary endpoint of the study was the number of episodes of mean arterial pressure (MAP) < 70 mmHg. Secondary endpoints were significant differences between the groups in MAP, heart rate, cardiac index, ejection fraction (EF; both measured with thoracic bioimpedance), calculated systemic vascular resistance index (SVRI), and central venous pressure.

MAIN RESULTS

The number of episodes of MAP < 70 mmHg did not differ between groups: there were 9 episodes in the ultrasound alone group and 7 in the radiofrequency group (P = 0.668). Cardiac index, EF, and SVRI were similar between groups. Central venous pressure was slightly higher in the radiofrequency group [11.99 (10.8-13.2) mmHg vs. 10.3 (9.2-11.4) mmHg, P = 0.04].

CONCLUSIONS

Hemodynamic profiles were similar when comparing laparoscopic radiofrequency ablation of liver metastases with laparoscopic ultrasound hepatic examination alone.

Modern diagnosis and management of hepatocellular carcinoma

The incidence of hepatocellular carcinoma (HCC) is rising, and the number of patients with HCC is expected to more than double over the next 1 to 2 decades. HCC meets the criteria for establishment of a surveillance program. Patients with cirrhosis, regardless of the cause, are at the highest risk for developing HCC and this is the population in which surveillance should be performed. (Alpha-fetoprotein and hepatic ultrasonography are the currently recommended surveillance tests. If a surveillance test is abnormal, there is a need for a recall test for diagnostic evaluation of HCC. Triple-phase imaging is recommended for evaluation at recall, with MRI being more sensitive and specific. Novel genetic markers can improve the histologic diagnosis of early HCC. The Barcelona staging classification is the best system for determining the prognosis of patients and it is linked to an evidence-based treatment algorithm. Resection, transplantation, and percutaneous ablation are considered curative interventions and are currently applied to about 30% of all patients with HCC.

Thermal ablation for hepatocellular carcinoma

Thermal ablation, as a form of minimally invasive therapy for hepatocellular carcinoma (HCC), has become an important treatment modality. Because of the limitations of surgery, the techniques of thermal ablation have become standard therapies for HCC in some situations. This article reviews 4 thermal ablation techniques-radiofrequency (RF) ablation, microwave ablation, laser ablation, and cryoablation. Each of these techniques may have a role in treating HCC, and the mechanisms, equipment, patient selection, results, and complications of each are considered. Furthermore, combined therapies consisting of thermal ablation and adjuvant chemotherapy also show promise for enhancing these techniques. Important areas of research into thermal ablation remain, including improving the ability of ablation to treat larger tumors, determining the indications for each thermal ablation modality, optimizing image guidance, and obtaining good outcome data on the efficacy of these techniques.

[Cryosurgery of primary and metastatic cancers of the liver]

Cryosurgery is a method of in situ destruction of tissue by a freezing process. Results of hepatic cryosurgery are now available for more than 2100 patients and allow to assess its place in the treatment of hepatic malignancies. Mechanisms of tissue destruction and indications of cryosurgery are detailed. With a peri-operative mortality rate of 1.5%, the safety of hepatic cryosurgery is now admitted. Cryosurgery has its own morbidity: increase of transaminases levels, platelets drop, myoglobinuria and rarely renal failure or cryoshock. In selected patients, hepatic cryosurgery is feasible with a laparoscopic or percutaneous approach. Long term results do not support cryosurgery as an alternative to liver resection. This technique enlarges possibilities of surgical treatment for patients with primary and metastatic liver cancers.