11/30/2015

Trusler Rules for Pulmonary Artery Banding

Banding material: 4-mm wide band of Teflon with silicone rubber coating.

General rules: For infants < 1 year of age -

(i) Left to right shunting, no other intracardiac mixing disorders: Can have relatively tight band. Therefore, band circumference = 20 mm + 1 mm/kg body weight.
(Hopefully, the Qp/Qs will be close to 1:1)

(ii) If there is ASD or MPA diameter is large, band can be slightly looser.
Therefore, add 1 or 2 mm to the band circumference.
(Reasons: Presence of large ASD will cause too much cyanosis which will not be tolerated. When MPA is large, band causes folds of arterial wall which will decrease the lumen size and therefore, will be equivalent to a tighter band).

(iii) Bidirectional shunting is present, TGA, etc. - Looser band is needed.
Therefore, band circumference = 24 + 1 mm/kg of body weight.
(In these circumstances, pulmonary blood flow needs to be close to Qp/Qs of 2:1 than 1:1).

(iv) In the presence of pulmonary hypertension, PA band is usually looser than above. The PA band is tightened until distal PA pressure is 50% of systemic pressure. (This was performed in 17 of 209 patients. These 17 patients were excluded from the study).

Intraoperative adjustments to the PA band size: The band should be loosened if (i) distal PA collpases, (ii) cyanosis or (iii) bradycardia occurs.

PA band should be more distal in babies who will undergo arterial switch operation later.

Reference:
Pulmonary Artery Banding. Albus RA, Trusler GA, Izukawa T and Williams WG. JTCVS 1984;88:645-653.

Preparing the band material - Letter to the editor. JTCVS 1984;88:792.

Trusler GA, Mustard WT. A method of banding the pulmonary artery for large isolated ventricular septal defect with and without TGA. Ann Thoracic Surg 1972;13:351-55.

Click here to see related post in Journal Club blog

11/18/2015

Development: Heart Tube & Looping

Images are from
An Introduction to Human Embryology for Medical Students by Inderbir Singh (5th ed).
MacMillan India Limited, Madras 1995.




(This 3rd figure is intentionally rotated to show in the same orientation as rest of the figures)


11/02/2015

Statins classification by potency

(Click on the image to enlarge)
From JACC 2014;63:2889-934.


Atorvastatin - Lipitor
Rosuvastatin - Crestor
Simvastatin - Zocor
Pravastatin - Pravachol
Lovastatin - Mevacor
Fluvastatin - Lescol
Pitavastatin - Livalo