Reevaluation of Histomorphometric Analysis of Lung Tissue in Decision Making for Better Patient Selection for Fontan-Type Operations

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Original article: cardiovascular

Reevaluation of Histomorphometric Analysis of Lung Tissue in Decision Making for Better Patient Selection for Fontan-Type Operations

Katsuhide Maeda, MD^a^,*, Shigeo Yamaki, MD^b, Hideaki Kado, MD^c, Toshihide Asou, MD^c, Arata Murakami, MD^a, Shinichi Takamoto, MD^a

^a Department of Cardiothoracic Surgery, Graduate School of Medicine, University of Tokyo, Tokyo, Japan
^b Japanese Research Institute of Pulmonary Vasculature, Shiroishi, Japan
^c Department of Thoracic and Cardiovascular Surgery, Fukuoka-City Children's Hospital, Fukuoka, Japan

Accepted for publication February 3, 2004.

^* Address reprint requests to Dr Maeda, Department of Cardiothoracic Surgery, Graduate School of Medicine, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8655, Japan
maedak-tky{at}umin.ac.jp

Presented at the Fortieth Annual Meeting of The Society of Thoracic Surgeons, San Antonio, TX, Jan 26–28, 2004.

BACKGROUND: The various types of cavopulmonary connection are occasionallyunsuccessful even when the indications have been strictly fulfilledbased on preoperative hemodynamic studies. We performed a detailedstudy of lung specimens from 60 patients who were judged tobe candidates for the modified Fontan procedures based on acatheterizaton study in order to reevaluate the role of histologicstudies of the pulmonary vasculature and to determine histologiccriteria for the Fontan-type operation.

METHODS: We performed a histomorphometric analysis of specimens from53 biopsy and 7 autopsy cases (0.5 to 23 years of age), withsingle ventricle physiology. Twenty-eight cases were treatedwith a bidirectional Glenn shunt (BDGS) and 32 cases were treatedby means of total cavopulmonary connections (TCPC) with or withoutfenestration, on the basis of the clinical and hemodynamic findings.To evaluate the medial thickness of small pulmonary arteries(SPAs), we used a measurement, D_{R = 100 µm}, that is unaffectedby various degrees of vasoconstriction of the media or the ageof the patients and that is representative of all SPAs in asection. Other variables, such as intimal lesions, SPA density,and the percentage of vessels containing a thrombus, were alsomeasured.

RESULTS: There was a significant difference in D_{R = 100 µm} valuesbetween the BDGS cases with good and bad outcomes at p = 0.0007(8.9 ± 2.4 versus 13.4 ± 1.9 µm), and thecutoff point for the success of BDGS was 13.7 µm. Thesame was true of the TCPC cases at p less than 0.0001 (8.4 ±1.7 versus 14.7 ± 1.5 µm), and the cutoff pointwas 11.6 µm. There were no significant differences inother histomorphometric variables. Investigation of the relationshipto hemodynamic data revealed a correlation between D_{R = 100µm} and mean pulmonary artery pressure at p = 0.028. Therewere no statistically significant correlations between othervariables.

CONCLUSIONS: The study revealed marked differences in D_{R = 100 µm} valuesbetween patients with good and bad outcomes and provided D_{R= 100 µm} cutoff points for BDGS and TCPC. In some cases,there were discrepancies between the results of the preoperativehemodynamic data and of the histomorphometric analysis; andbecause some patients were wrongly assessed based on clinicaland hemodynamic criteria, histomorphometric study might be auseful method of supplementing the variety of clinical dataused to determine the indications for this operation.