Regarding "The incidence of deep venous thrombosis in patients undergoing abdominal aortic aneurysm resection"

LETTERS TO T H E E D I T O R S The Editors invite readers to submit letters commenting on the contents of articles that appear in the JOURNAL.Also welcome are brief communications in letter form reporting investigative or clinical observations without extensive documentation and with brief bibliography (five titles or less), not requiring peer review but open to critique by readers. Letters to the Editors should be no more than 500 words in length and they may have to be edited for publication.

Regarding the posterior approach to crural arteries To the Editors:

The resurrection of the posterior approach to the crural arteries has been achieved with the publications of Ouriel (J VAsc SURG 1994;19:74-80) and Mukherjee (J VASC SURG 1994;19:174-8). Both of these authors properly emphasize the importance of this approach, one that needs to be included in the armamentarium of all vascular surgeons performing distal lower extremity bypass. My concern, however, is for the comments made by Dr. Mukherjee regarding the lateral approach to the peroneal artery. He states that this method, with the segmental resection of the fibula, results in lymphatic disruption, postoperative pain, and distal lower extremity edema. Having now performed more than 300 such procedures, I can unequivocally state that this is not the case. The incidence and extent of edema and postoperative pain is not unlike that attendant to any other revascularization procedure in the lower extremity not requiring fibular resection. In fact, most of my patients indicate that their preoperative ischemic pain was of such severity that their comfort level after surgery was most gratifying. Finally, the comment regarding lymphatic disruption is simply lumped with the events that occur with harvesting the greater saphenous vein, a procedure that is obviously on the other side of the limb and in no way related to the subperiosteal resection of the fibula. Fibular resection does not interfere with the patient's postoperative rehabilitation and resumption of normal bipedal gait. The posterior approach should not be considered as competitive to the medial or lateral approach but rather as an additional option with particular indications that might make it more appropriate in one instance than another. Herbert Dardik, MD

Englewood Hospital 375 Engle St. Englewood, NJ 07631

REFERENCE 1. Dardik H, et al. Exposure of the tibial peroneal arteries by a single lateral approach. Surg 1974;75:377-82. 24/41/56099 Reply To the Editors:

Thank you for sharing Dr. Dardik's letter regarding the publication "Posterior approach to the peroneal artery," which appeared in the January issue of the JOURNAL OE VASCULAR SURGERY.

318 JOURNAL OF VASCULAR SURGERY/August 1994

We are indeed indebted to Dr. Dardik for the numerous contributions that he has made in the field of lower extremity arterial reconstruction. The posterior approach to peroneal artery reconstruction was not meant to be a competitive approach to the lateral approach described by him. It is offered as an additional exposure to what can sometimes be a challenging reconstruction. Although the lateral approach does provide good exposure of the peroneal artery, it does involve resecting the fibula, which is certainly more disruptive than approaching the vessel without having to resect bone. As far as your comments regarding lower extremity swelling occurring after the bypass is concerned, I do agree that the distal edema is largely on the basis of lymphatic disruption, associated with harvesting the greater saphenous vein. The lateral approach to the peroneal artery as such would not make this problem any worse than it usually is. I thank you for your constructive criticism of the manuscript. Dipankar Mukherjee, MD, FA CS, R VT

3301 Woodburn Rd., no. 110 Annandale, VA 22003 24/41/56100 Regarding "The incidence o f deep venous thrombosis in patients undergoing abdominal aortic

aneurysm resection" To the Editors:

We read with interest the article by Olin et al. (J VASC SURG 1993;18:1037-41), in which they report that in nine (18%) of 50 patients undergoing elective abdominal aortic aneurysm (AAA) resection, deep venous thrombosis (DVT) developed as shown by venography on the fifth postoperative day. We have recently reviewed our last 65 patients who underwent operation for ruptured AAA and found a clear association between the development of a postoperative thrombocytosis (platelet count > 400 × 109/L) and thromboembolic complications in the 35 survivors (Table I).In all cases the clinical diagnosis was confirmed by duplex ultrasonography, venography, or ventilation/perfusion scanning. There was a significant correlation between the postoperative day (POD) on which the D V T became clinically apparent (median 10, range 7 to 22) and the P O D on which the platelet count first exceeded 400 × 103/mm 3 (median 11, range 4 to 30, r 2 = 0.79, p < 0.01). There

JOURNAL OF VASCULARSURGERY Volume 20, Number 2

Letters to the Editors

319

Table I. Association between postoperative thrombocytosis after successful repair of ruptured AAA and thromboembolic complications Thromboembolic event

Thrombocytosis (n = 15)

No thrombocytosis (n = 20)

Deep venous thrombosis Deep venous thrombosis and pulmonary embolism None

10 (1) 8 (0) 5 (4)

20 (8)

Numbers in brackets denote patients receiving post operative low-dose heparin.

was also a significant correlation between the POD on which the DVT became clinically apparent and the day on which the maximum platelet count (median 523, range 416 to 728 × 103/mm 3) was attained (median 15, range 7 to 33, r 2 = 0.80,p < 0.01). Our review indicates that 40% of patients surviving operation for ruptured AAA develop a thrombocytosis during the postoperative period that may persist for several weeks. Thrombocytosis appears to be strongly associated with the development of post-operative thromboembolic events. To our knowledge this is the first report of such an association in patients undergoing AAA surgery. The cause of the thrombocytosis is unknown and is an area that we are currently investigating. However, it appears from our data that postoperative low-dose heparin therapy (5000 IU subcutaneously twice daily) may reduce both the postoperative rise in platelet count and the risk of thromboembolism. It is clear from our own data and the study by Olin that thromboembolism is a common and potentially lifethreatening complication in this group of patients that may previously have been underestimated. In the absence of concerns about hemorrhage, we now routinely prescribe low-dose heparin from the first postoperative day. Finally, we would be most interested to know whether Olin and his colleagues found such an association between DVT and thrombocytosis in their patients.

abdominal aortic aneurysm (AAA). They also noted a significant correlation between the postoperative day in which the deep vein thrombosis became clinically apparent and the postoperative day in which the platelet count exceeded 400 × 10S/mm 3. In reviewing our series, eight of the nine patients in whom deep venous thrombosis developed after elective AAA surgery had platelet counts less than 400 × 103/ram 3 every day after operation. One patient had a platelet count of 468 × 10S/mm 3 on the fifth postoperative day. There are some differences between our series and the series of Bradbury. All of our patients underwent elective repair of the AAA, and all of their patients underwent operation on for ruptured AAA. All of their patients had symptoms of deep venous thrombosis, whereas none of ours did. Postoperative thrombocytosis is not an uncommon finding. It has been shown in numerous studies that reactive thrombocytosis rarely causes hemorrhagic or thrombotic complications. 2,s Coon et al.4 have shown that deep venous thrombosis developed in five of 86 patients undergoing elective splenectomy. In none of these five patients did an elevation in platelet count to 600 x 103/ram 3 develop before or at the time of the thrombosis. 4 Venous thrombosis did not develop in any of the 21 patients who had rises in the platelet count to greater than 1 million.

Andrew Bradbury, BSc, 214_19,FRCS Alan Milne, A4B, ChB

Jeffrey W.. Olin, DO Robert A. Graor, BiD Patrick J. O'Hara, M_D Jess tL Young, A4D

Vascular Surgery Unit University Department of Surgery Royal Infirmary Edinburgh, Scotland, UK, EH3 9YW Paul Bachoo, FRCS John Duncan, ChM, FRCS

Department of General Surgery Raigmore Hospital Inverness, Scotland, United Kingdom, IV2 3UJ 24/41/56103

Reply To the Editors:

Bradbury and colleagues have noted a high incidence of postoperative thrombocytosis (platelet count greater than 400 × 103/ram 3) and thromboembolic complications in the 35 survivors who underwent operation for ruptured

Cleveland Clinic Foundation 9500 Euclid Ave. Cleveland, OH 44195 REFERENCES

1. Olin JW, Graor RA, O'Hara PJ, Young JR. The incidence of deep venous thrombosis in patients undergoing abdominal aortic aneurysm resection. J VAsc SURe 1993;18:1037-41. 2. Buss DH, Stuart J~, Lipscomb GE. The incidence of thromboric and hemorrhagic disorders in association with extreme thrombocytosis: an analysis of 129 cases. Am J Hematol 1985;20:365-72. 3. Schafer AI. Bleeding and thrombosis in myeloproliferative disorders. Blood 1984;64:1-12. 4. Coon WW, Penner J, Clagett GP, Eos N. Deep venous thrombosis and postsplenectomy thrombocytosis. Arch Surg 1978;113:429-31. 24/41/56104