Man With Constant Pain in Left Foot
A 62-year-old man is admitted for left foot pain. He has had pain in the left lower leg and foot for several months, but now the pain in the left foot has become constant, including at night when it keeps him awake. Up until about 2 to 4 weeks ago, he had a cramping pain in the calf and instep with walking that would resolve if he sat down. That pattern was replaced by the constant pain he feels now.
HISTORY
Because the patient is unemployed and lives in a shelter, he has not received any medical care in a long time. His past medical history includes “emphysema-bronchitis” and hypertension, but he currently takes no medications. He also has a history of heavy tobacco use, which has diminished, and he now smokes about a half pack per day.
PHYSICAL EXAMINATION
This somewhat disheveled man is in mild distress from left foot discomfort. Vital signs include a blood pressure of 160/98 mm Hg and oxygen saturation of 98% on room air. He is thin and has nicotine staining of the fingers of his right hand.
His lower extremities are the focus of the examination abnormalities. His right leg is normal, including palpable femoral, popliteal, dorsalis pedis, and posterior tibial pulses. The left leg has a palpable femoral pulse, but the popliteal, dorsalis pedis, and posterior tibial pulses are absent. The left foot is pale, compared with the right one, and has atrophic skin changes and ulcerations at the lateral malleolus and tips of the first two toes. No bullae are noted. Sensation is decreased on the left from the foot to mid-shin.
IMAGING RESULTS
Plain x-ray films are negative for osteomyelitis and subcutaneous gas. CT studies reveal significant calcification and atherosclerosis of the infra-renal aorta and femoral arteries.
Which of the following statements is correct?
A. A variety of management techniques result in overall good prognosis in this patient group.
B. He should receive a 4- to 6-week trial of good medical management with smoking cessation, anticoagulants, and physical therapy.
C. Endovascular revascularization techniques will be the methods of choice should he require an intervention.
D. His findings likely warrant urgent surgical revascularization.
(Answer on next page)
Answer: D, His findings likely warrant urgent surgical revascularization.
This patient’s underlying condition is peripheral arterial disease (PAD), and he exhibits many of the classic risk factors, signs, and symptoms. Risk factors include smoking, diabetes, hypertension, and hyperlipidemia.1
A classic symptom he displayed is intermittent claudication—leg pain with exertion relieved by resting. His physical examination demonstrated a difference in pulses between the symptomatic and asymptomatic leg, and a highly abnormal ankle-brachial index (obtained by comparing the Doppler ultrasound pressures in the brachial, dorsalis pedis, and posterior tibial arteries) confirmed the diagnosis.1
Unfortunately, he now presents with an advanced, dangerous, and morbid manifestation of PAD—rest pain, along with very worrisome Doppler and clinical findings (see below) all consistent with acute limb ischemia, defined as a sudden decrease in perfusion that threatens the viability of the limb.2 This sudden cessation of blood supply affects various tissues of the limb—namely, skin, muscle, and nerve—thus resulting in the constellation of findings, several of which are present in this patient, of pain (even at rest and at night, very different from the classic pattern of intermittent claudication typical of chronic ischemia), sensory loss, and some degree of muscle weakness. According to the classic Society for Vascular Surgery standards,3 this patient would seem to have at least category IIb ischemia: limb immediately threatened, salvageable with immediate revascularization. The Doppler evaluation, indicating the absence of any flow to the dorsalis pedis and posterior tibial arteries, confirms the total absence of perfusion below the knee.
CAUSES OF ACUTE LIMB ISCHEMIA
Causes of acute limb ischemia include embolism from the heart (eg, atrial fibrillation), trauma or, as is most likely in any patient and even more so in this patient who had classic claudication in the months before presentation, an acute thrombosis at the site of an atherosclerotic plaque. Medical conditions causing thrombosis in a previously healthy artery include certain thrombophilias, such as antiphospholipid antibody syndrome and heparin-induced thrombocytopenia. It should be noted that acute limb ischemia is a morbid and dangerous situation, resulting from both the acute event and its therapy as well as the frequent underlying conditions. Even with proper acute management, amputation will result in 10% to 15% of cases during the hospitalization and some 15% to 20% of patients will die within 1 year.4 Thus, choice A is far too optimistic and is not a correct statement.
TREATMENT OF ACUTE LIMB ISCHEMIA
Therapy in any case of acute limb ischemia requires attempts to immediately restore blood flow. In the very brief period of further evaluation (eg, Doppler evaluations, angiography), heparinization is acutely used to stop thrombus propagation. As previously discussed, the staging of acute limb ischemia provides a guide to whether or not the limb is viable or marginally threatened or is immediately or irreversibly threatened.2 Then time of onset is incorporated: 2 weeks is the accepted timeline as regards using an endovascular approach versus an open surgical approach (endovascular if the onset is less than 2 weeks earlier; open surgical if the onset is more than 2 weeks earlier).
Endovascular approaches include catheter-directed thrombolytic agents and catheter-placed endovascular stents, or a combination of the two. Surgical revascularization methods include thrombectomy, patch angioplasty, intraoperative thrombolysis, and bypass surgery, either alone or more commonly in combination. When the acute thrombosis has resulted as a complication of chronic arterial disease, as in this patient, correction of the underlying arterial abnormality is mandatory for a successful result. As alluded to above, meta-analysis of randomized trials and case series indicates that endovascular techniques work best with viable or marginally threatened limbs of recent (less than 2 weeks) onset with at least one competent distal runoff vessel; whereas a surgical technique offers the best results in a more immediately threatened limb or with symptoms of more than 2 weeks’ duration or with very poor local anatomy.2,5
Thus, choice B (a very conservative medical regimen) is far too conservative for the facts at hand in this case and is not optimal here. Even choice C (endovascular revascularization) is not likely the most efficacious method in this patient, since he has at least 2 criteria for a surgical approach—he has category IIb ischemia with an immediately threatened limb and the onset seems very close to at least 2 weeks ago. Thus, choice D is the best alternative here.
OUTCOME OF THIS CASE
Urgent angiography confirmed significant, widespread atherosclerosis obliterans with an acute thrombosis at a plaque site above the popliteal artery and very problematic distal runoff vessels. Nonetheless, an attempt at surgical thrombectomy with patch angioplasty was performed. The patient had a stormy postoperative course with several re-occlusions and required an above the knee amputation on day 9.
REFERENCES:
- Hiatt WR. Medical treatment of peripheral arterial disease and claudication. N Engl J Med. 2001;344:1608-1621.
- Creager MA, Kaufman JA, Conte MS. Acute limb ischemia. N Engl J Med. 2012;366:2198-2206.
- Rutherford RB, Baker JD, Ernst C, et al. Recommended standards for reports dealing with lower extremity ischemia: revised version. J Vasc Surg. 1997;26:517-538.
- Henke K. Contemporary management of acute limb ischemia: factors associated with amputation and in-hospital mortality. Semin Vasc Surg. 2009;22:34-40.
- Comerota AJ, Gravett MH. Do randomized trials of thrombolysis versus open revascularization still apply to current management: what has changed? Semin Vasc Surg. 2009;22:41-46.